diff --git a/pkgs/typed-racket-pkgs/typed-racket-doc/typed-racket/scribblings/reference/libraries.scrbl b/pkgs/typed-racket-pkgs/typed-racket-doc/typed-racket/scribblings/reference/libraries.scrbl
index 2135ac92..1a759e9a 100644
--- a/pkgs/typed-racket-pkgs/typed-racket-doc/typed-racket/scribblings/reference/libraries.scrbl
+++ b/pkgs/typed-racket-pkgs/typed-racket-doc/typed-racket/scribblings/reference/libraries.scrbl
@@ -71,6 +71,7 @@ The following libraries are included with Typed Racket in the
 @defmodule/incl[typed/openssl/md5]
 @defmodule/incl[typed/openssl/sha1]
 @defmodule/incl[typed/pict]
+@defmodule/incl[typed/racket/async-channel]
 @defmodule/incl[typed/rackunit]
 @defmodule/incl[typed/srfi/14]
 @defmodule/incl[typed/syntax/stx]
diff --git a/pkgs/typed-racket-pkgs/typed-racket-doc/typed-racket/scribblings/reference/types.scrbl b/pkgs/typed-racket-pkgs/typed-racket-doc/typed-racket/scribblings/reference/types.scrbl
index 607ab4ff..58952de3 100644
--- a/pkgs/typed-racket-pkgs/typed-racket-doc/typed-racket/scribblings/reference/types.scrbl
+++ b/pkgs/typed-racket-pkgs/typed-racket-doc/typed-racket/scribblings/reference/types.scrbl
@@ -4,7 +4,8 @@
                 "numeric-tower-pict.rkt"
                 scribble/eval
                 racket/sandbox)
-       (require (for-label (only-meta-in 0 [except-in typed/racket for])))]
+       (require (for-label (only-meta-in 0 [except-in typed/racket for])
+                           racket/async-channel))]
 
 @(define the-eval (make-base-eval))
 @(the-eval '(require (except-in typed/racket #%top-interaction #%module-begin)))
@@ -412,6 +413,21 @@ corresponding to @racket[trest], where @racket[bound]
 @ex[(lambda: ([x : Any]) (if (channel? x) x (error "not a channel!")))]
 }
 
+@defform[(Async-Channelof t)]{An @rtech{asynchronous channel} on which only @racket[t]s can be sent.
+@ex[
+(require typed/racket/async-channel)
+(ann (make-async-channel) (Async-Channelof Symbol))
+]
+}
+
+@defidform[Async-ChannelTop]{is the type of an @rtech{asynchronous channel} with unknown
+  message type and is the supertype of all asynchronous channel types. This type typically
+  appears in programs via the combination of occurrence typing and
+  @racket[async-channel?].
+@ex[(require typed/racket/async-channel)
+    (lambda: ([x : Any]) (if (async-channel? x) x (error "not an async-channel!")))]
+}
+
 @defform*[[(Parameterof t)
            (Parameterof s t)]]{A @rtech{parameter} of @racket[t].  If two type arguments are supplied,
                                  the first is the type the parameter accepts, and the second is the type returned.
diff --git a/pkgs/typed-racket-pkgs/typed-racket-lib/typed-racket/base-env/base-types.rkt b/pkgs/typed-racket-pkgs/typed-racket-lib/typed-racket/base-env/base-types.rkt
index 8c413217..cff177c5 100644
--- a/pkgs/typed-racket-pkgs/typed-racket-lib/typed-racket/base-env/base-types.rkt
+++ b/pkgs/typed-racket-pkgs/typed-racket-lib/typed-racket/base-env/base-types.rkt
@@ -115,6 +115,7 @@
 [Procedure top-func]
 [BoxTop -BoxTop]
 [ChannelTop -ChannelTop]
+[Async-ChannelTop -Async-ChannelTop]
 [VectorTop -VectorTop]
 [HashTableTop -HashTop]
 [MPairTop -MPairTop]
@@ -168,6 +169,7 @@
 [Pair (-poly (a b) (-pair a b))]
 [Boxof (-poly (a) (make-Box a))]
 [Channelof (-poly (a) (make-Channel a))]
+[Async-Channelof (-poly (a) (make-Async-Channel a))]
 [Ephemeronof (-poly (a) (make-Ephemeron a))]
 [Setof (-poly (e) (make-Set e))]
 [Evtof (-poly (r) (-evt r))]
diff --git a/pkgs/typed-racket-pkgs/typed-racket-lib/typed-racket/infer/infer-unit.rkt b/pkgs/typed-racket-pkgs/typed-racket-lib/typed-racket/infer/infer-unit.rkt
index 7ccdd633..9da19828 100644
--- a/pkgs/typed-racket-pkgs/typed-racket-lib/typed-racket/infer/infer-unit.rkt
+++ b/pkgs/typed-racket-pkgs/typed-racket-lib/typed-racket/infer/infer-unit.rkt
@@ -592,6 +592,8 @@
            (% cset-meet (cg/inv s s*) (cg/inv t t*))]
           [((Channel: e) (Channel: e*))
            (cg/inv e e*)]
+          [((Async-Channel: e) (Async-Channel: e*))
+           (cg/inv e e*)]
           [((ThreadCell: e) (ThreadCell: e*))
            (cg/inv e e*)]
           [((Continuation-Mark-Keyof: e) (Continuation-Mark-Keyof: e*))
@@ -629,6 +631,7 @@
                t)]
           [((CustodianBox: t) (Evt: t*)) (cg S t*)]
           [((Channel: t) (Evt: t*)) (cg t t*)]
+          [((Async-Channel: t) (Evt: t*)) (cg t t*)]
           ;; we assume all HTs are mutable at the moment
           [((Hashtable: s1 s2) (Hashtable: t1 t2))
            ;; for mutable hash tables, both are invariant
diff --git a/pkgs/typed-racket-pkgs/typed-racket-lib/typed-racket/private/type-contract.rkt b/pkgs/typed-racket-pkgs/typed-racket-lib/typed-racket/private/type-contract.rkt
index ff519b24..f0ff5618 100644
--- a/pkgs/typed-racket-pkgs/typed-racket-lib/typed-racket/private/type-contract.rkt
+++ b/pkgs/typed-racket-pkgs/typed-racket-lib/typed-racket/private/type-contract.rkt
@@ -330,6 +330,7 @@
         [(VectorTop:) (only-untyped vector?/sc)]
         [(BoxTop:) (only-untyped box?/sc)]
         [(ChannelTop:) (only-untyped channel?/sc)]
+        [(Async-ChannelTop:) (only-untyped async-channel?/sc)]
         [(HashtableTop:) (only-untyped hash?/sc)]
         [(MPairTop:) (only-untyped mpair?/sc)]
         [(ThreadCellTop:) (only-untyped thread-cell?/sc)]
diff --git a/pkgs/typed-racket-pkgs/typed-racket-lib/typed-racket/rep/type-rep.rkt b/pkgs/typed-racket-pkgs/typed-racket-lib/typed-racket/rep/type-rep.rkt
index 75c1378c..dc5f3c21 100644
--- a/pkgs/typed-racket-pkgs/typed-racket-lib/typed-racket/rep/type-rep.rkt
+++ b/pkgs/typed-racket-pkgs/typed-racket-lib/typed-racket/rep/type-rep.rkt
@@ -185,6 +185,11 @@
   [#:frees (λ (f) (make-invariant (f elem)))]
   [#:key 'channel])
 
+;; elem is a Type
+(def-type Async-Channel ([elem Type/c])
+  [#:frees (λ (f) (make-invariant (f elem)))]
+  [#:key 'async-channel])
+
 ;; elem is a Type
 (def-type ThreadCell ([elem Type/c])
   [#:frees (λ (f) (make-invariant (f elem)))]
@@ -397,6 +402,7 @@
 ;; the supertype of all of these values
 (def-type BoxTop () [#:fold-rhs #:base] [#:key 'box])
 (def-type ChannelTop () [#:fold-rhs #:base] [#:key 'channel])
+(def-type Async-ChannelTop () [#:fold-rhs #:base] [#:key 'async-channel])
 (def-type VectorTop () [#:fold-rhs #:base] [#:key 'vector])
 (def-type HashtableTop () [#:fold-rhs #:base] [#:key 'hash])
 (def-type MPairTop () [#:fold-rhs #:base] [#:key 'mpair])
diff --git a/pkgs/typed-racket-pkgs/typed-racket-lib/typed-racket/static-contracts/combinators/derived.rkt b/pkgs/typed-racket-pkgs/typed-racket-lib/typed-racket/static-contracts/combinators/derived.rkt
index 43f5bd31..09832f6a 100644
--- a/pkgs/typed-racket-pkgs/typed-racket-lib/typed-racket/static-contracts/combinators/derived.rkt
+++ b/pkgs/typed-racket-pkgs/typed-racket-lib/typed-racket/static-contracts/combinators/derived.rkt
@@ -6,7 +6,7 @@
 
 (require "simple.rkt" "structural.rkt"
          (for-template racket/base racket/list racket/set racket/promise racket/mpair
-                       racket/class))
+                       racket/class racket/async-channel))
 (provide (all-defined-out))
 
 (define identifier?/sc (flat/sc #'identifier?))
@@ -28,6 +28,7 @@
 (define empty-hash/sc (and/sc hash?/sc (flat/sc #'(λ (h) (zero? (hash-count h))))))
 
 (define channel?/sc (flat/sc #'channel?))
+(define async-channel?/sc (flat/sc #'channel?))
 (define thread-cell?/sc (flat/sc #'thread-cell?))
 (define prompt-tag?/sc (flat/sc #'continuation-prompt-tag?))
 (define continuation-mark-key?/sc (flat/sc #'continuation-mark-key?))
diff --git a/pkgs/typed-racket-pkgs/typed-racket-lib/typed-racket/types/abbrev.rkt b/pkgs/typed-racket-pkgs/typed-racket-lib/typed-racket/types/abbrev.rkt
index 70e85e7c..18aa0f7a 100644
--- a/pkgs/typed-racket-pkgs/typed-racket-lib/typed-racket/types/abbrev.rkt
+++ b/pkgs/typed-racket-pkgs/typed-racket-lib/typed-racket/types/abbrev.rkt
@@ -54,6 +54,7 @@
 (define -Param make-Param)
 (define -box make-Box)
 (define -channel make-Channel)
+(define -async-channel make-Async-Channel)
 (define -thread-cell make-ThreadCell)
 (define -Promise make-Promise)
 (define -set make-Set)
@@ -169,6 +170,7 @@
 (define -HT make-Hashtable)
 (define/decl -BoxTop (make-BoxTop))
 (define/decl -ChannelTop (make-ChannelTop))
+(define/decl -Async-ChannelTop (make-Async-ChannelTop))
 (define/decl -HashTop (make-HashtableTop))
 (define/decl -VectorTop (make-VectorTop))
 (define/decl -MPairTop (make-MPairTop))
diff --git a/pkgs/typed-racket-pkgs/typed-racket-lib/typed-racket/types/printer.rkt b/pkgs/typed-racket-pkgs/typed-racket-lib/typed-racket/types/printer.rkt
index 7f193e33..60921782 100644
--- a/pkgs/typed-racket-pkgs/typed-racket-lib/typed-racket/types/printer.rkt
+++ b/pkgs/typed-racket-pkgs/typed-racket-lib/typed-racket/types/printer.rkt
@@ -424,6 +424,7 @@
     [(StructTop: (Struct: nm _ _ _ _ _)) `(Struct ,(syntax-e nm))]
     [(BoxTop:) 'BoxTop]
     [(ChannelTop:) 'ChannelTop]
+    [(Async-ChannelTop:) 'Async-ChannelTop]
     [(ThreadCellTop:) 'ThreadCellTop]
     [(VectorTop:) 'VectorTop]
     [(HashtableTop:) 'HashTableTop]
@@ -462,6 +463,7 @@
     [(Box: e) `(Boxof ,(t->s e))]
     [(Future: e) `(Futureof ,(t->s e))]
     [(Channel: e) `(Channelof ,(t->s e))]
+    [(Async-Channel: e) `(Async-Channelof ,(t->s e))]
     [(ThreadCell: e) `(ThreadCellof ,(t->s e))]
     [(Promise: e) `(Promise ,(t->s e))]
     [(Ephemeron: e) `(Ephemeronof ,(t->s e))]
diff --git a/pkgs/typed-racket-pkgs/typed-racket-lib/typed-racket/types/structural.rkt b/pkgs/typed-racket-pkgs/typed-racket-lib/typed-racket/types/structural.rkt
index 0b51cd3f..13154f0e 100644
--- a/pkgs/typed-racket-pkgs/typed-racket-lib/typed-racket/types/structural.rkt
+++ b/pkgs/typed-racket-pkgs/typed-racket-lib/typed-racket/types/structural.rkt
@@ -32,6 +32,7 @@
 (define-for-syntax structural-reps
   #'([BoxTop ()]
      [ChannelTop ()]
+     [Async-ChannelTop ()]
      [ClassTop ()]
      [Continuation-Mark-KeyTop ()]
      [Error ()]
@@ -62,6 +63,7 @@
      [Continuation-Mark-Keyof (#:inv)]
      [Box (#:inv)]
      [Channel (#:inv)]
+     [Async-Channel (#:inv)]
      [ThreadCell (#:inv)]
      [Vector (#:inv)]
      [Hashtable (#:inv #:inv)]
diff --git a/pkgs/typed-racket-pkgs/typed-racket-lib/typed-racket/types/subtype.rkt b/pkgs/typed-racket-pkgs/typed-racket-lib/typed-racket/types/subtype.rkt
index 2f9b5276..95480b8c 100644
--- a/pkgs/typed-racket-pkgs/typed-racket-lib/typed-racket/types/subtype.rkt
+++ b/pkgs/typed-racket-pkgs/typed-racket-lib/typed-racket/types/subtype.rkt
@@ -510,6 +510,7 @@
           ;; compared against t* here
           (subtype* A0 s t*)]
          [((Channel: t) (Evt: t*)) (subtype* A0 t t*)]
+         [((Async-Channel: t) (Evt: t*)) (subtype* A0 t t*)]
          ;; Invariant types
          [((Box: s) (Box: t)) (type-equiv? A0 s t)]
          [((Box: _) (BoxTop:)) A0]
@@ -517,6 +518,8 @@
          [((ThreadCell: _) (ThreadCellTop:)) A0]
          [((Channel: s) (Channel: t)) (type-equiv? A0 s t)]
          [((Channel: _) (ChannelTop:)) A0]
+         [((Async-Channel: s) (Async-Channel: t)) (type-equiv? A0 s t)]
+         [((Async-Channel: _) (Async-ChannelTop:)) A0]
          [((Vector: s) (Vector: t)) (type-equiv? A0 s t)]
          [((Vector: _) (VectorTop:)) A0]
          [((HeterogeneousVector: _) (VectorTop:)) A0]
diff --git a/pkgs/typed-racket-pkgs/typed-racket-more/typed/racket/async-channel.rkt b/pkgs/typed-racket-pkgs/typed-racket-more/typed/racket/async-channel.rkt
new file mode 100644
index 00000000..912613d0
--- /dev/null
+++ b/pkgs/typed-racket-pkgs/typed-racket-more/typed/racket/async-channel.rkt
@@ -0,0 +1,16 @@
+#lang s-exp typed-racket/base-env/extra-env-lang
+
+;; This module provides a typed version of racket/async-channel
+
+(require "private/async-channel-wrapped.rkt"
+         (for-syntax (only-in (rep type-rep) make-Async-ChannelTop)))
+
+;; Section 11.2.4 (Buffered Asynchronous Channels)
+(type-environment
+ [make-async-channel (-poly (a) (->opt [(-opt -PosInt)] (-async-channel a)))]
+ [async-channel? (make-pred-ty (make-Async-ChannelTop))]
+ [async-channel-get (-poly (a) ((-async-channel a) . -> . a))]
+ [async-channel-try-get (-poly (a) ((-async-channel a) . -> . (-opt a)))]
+ [async-channel-put (-poly (a) ((-async-channel a) a . -> . -Void))]
+ [async-channel-put-evt (-poly (a) (-> (-async-channel a) a (-mu x (-evt x))))])
+
diff --git a/pkgs/typed-racket-pkgs/typed-racket-test/tests/typed-racket/fail/async-channel-contract.rkt b/pkgs/typed-racket-pkgs/typed-racket-test/tests/typed-racket/fail/async-channel-contract.rkt
new file mode 100644
index 00000000..fb3b2795
--- /dev/null
+++ b/pkgs/typed-racket-pkgs/typed-racket-test/tests/typed-racket/fail/async-channel-contract.rkt
@@ -0,0 +1,19 @@
+#;
+(exn-pred #rx"could not convert type to a contract.*Async-Channelof")
+#lang racket/load
+
+;; Test typed-untyped interaction with channels
+
+(module typed typed/racket
+  (require typed/racket/async-channel)
+  (: ch (Async-Channelof (Boxof Integer)))
+  (define ch (make-async-channel))
+  (: putter (-> Thread))
+  (define (putter)
+    (thread (λ () (async-channel-put ch (box 3)))))
+  (provide putter ch))
+
+(require 'typed)
+(putter)
+(set-box! (async-channel-get ch) "not an integer")
+
diff --git a/pkgs/typed-racket-pkgs/typed-racket-test/tests/typed-racket/succeed/events-with-async-channel.rkt b/pkgs/typed-racket-pkgs/typed-racket-test/tests/typed-racket/succeed/events-with-async-channel.rkt
new file mode 100644
index 00000000..60c163a2
--- /dev/null
+++ b/pkgs/typed-racket-pkgs/typed-racket-test/tests/typed-racket/succeed/events-with-async-channel.rkt
@@ -0,0 +1,106 @@
+#lang typed/racket
+(require typed/racket/async-channel)
+
+;; Integration test for synchronizable events, using async-channels
+;;
+;; example from unstable/logging
+
+(define-type Log-Receiver-Sync-Result
+  (Vector Symbol String Any (Option Symbol)))
+
+(: receiver-thread
+   (Log-Receiver (Async-Channelof 'stop)
+    (Log-Receiver-Sync-Result -> Void)
+    -> Thread))
+(define (receiver-thread receiver stop-chan intercept)
+  (thread
+   (lambda ()
+     (: clear-events (-> Void))
+     (define (clear-events)
+       (let ([l : (Option Log-Receiver-Sync-Result)
+               (sync/timeout 0 receiver)])
+         (when l ; still something to read
+           (intercept l) ; interceptor gets the whole vector
+           (clear-events))))
+     (let loop ()
+       (let ([l : (U Log-Receiver-Sync-Result 'stop)
+               (sync receiver stop-chan)])
+         (cond [(eq? l 'stop)
+                ;; we received all the events we were supposed
+                ;; to get, read them all (w/o waiting), then
+                ;; stop
+                (clear-events)]
+               [else ; keep going
+                (intercept l)
+                (loop)]))))))
+
+(struct: listener ([stop-chan : (Async-Channelof 'stop)]
+                   ;; ugly, but the thread and the listener need to know each
+                   ;; other
+                   [thread : (Option Thread)]
+                   [rev-messages : (Listof Log-Receiver-Sync-Result)]
+                   [done? : Any])
+          #:mutable)
+
+(: start-recording (Log-Level -> listener))
+(define (start-recording log-level)
+  (let* ([receiver     (make-log-receiver (current-logger) log-level)]
+         [stop-chan    ((inst make-async-channel 'stop))]
+         [cur-listener (listener stop-chan #f '() #f)]
+         [t (receiver-thread
+             receiver stop-chan
+             (lambda: ([l : Log-Receiver-Sync-Result])
+               (set-listener-rev-messages!
+                cur-listener
+                (cons l (listener-rev-messages cur-listener)))))])
+    (set-listener-thread! cur-listener t)
+    cur-listener))
+
+(: stop-recording (listener -> (Listof Log-Receiver-Sync-Result)))
+(define (stop-recording cur-listener)
+  (define the-thread (listener-thread cur-listener))
+  (unless (or (not the-thread)
+              (listener-done? cur-listener))
+    (async-channel-put (listener-stop-chan cur-listener)
+                 'stop) ; stop the receiver thread
+    (thread-wait the-thread)
+    (set-listener-done?! cur-listener #t))
+  (reverse (listener-rev-messages cur-listener)))
+
+(: with-intercepted-logging
+   (((Vector Symbol String Any (Option Symbol)) -> Void)
+    (-> Void)
+    Log-Level
+    -> Void))
+(define (with-intercepted-logging interceptor proc log-level)
+  (let* ([orig-logger (current-logger)]
+         ;; We use a local logger to avoid getting messages that didn't
+         ;; originate from proc. Since it's a child of the original logger,
+         ;; the rest of the program still sees the log entries.
+         [logger      (make-logger #f orig-logger)]
+         [receiver    (make-log-receiver logger log-level)]
+         [stop-chan   ((inst make-async-channel 'stop))]
+         [t           (receiver-thread receiver stop-chan interceptor)])
+    (begin0
+        (parameterize ([current-logger logger])
+          (proc))
+      (async-channel-put stop-chan 'stop) ; stop the receiver thread
+      (thread-wait t))))
+
+(require typed/rackunit)
+
+;; extracted from unstable/logging tests
+(let ([l (start-recording 'warning)])
+  (log-warning "1")
+  (log-warning "2")
+  (log-warning "3")
+  (log-info "4")
+  (stop-recording l) ; stopping should be idempotent
+  (let ([out (stop-recording l)])
+    (check-equal? (map (lambda: ([l : Log-Receiver-Sync-Result])
+                         (vector-ref l 1)) out)
+                  '("1" "2" "3"))
+    (check-true (andmap (lambda: ([l : Log-Receiver-Sync-Result])
+                          (eq? (vector-ref l 0) 'warning))
+                        out))))
+
diff --git a/pkgs/typed-racket-pkgs/typed-racket-test/tests/typed-racket/succeed/make-top-predicate.rkt b/pkgs/typed-racket-pkgs/typed-racket-test/tests/typed-racket/succeed/make-top-predicate.rkt
index 30322ace..897ea142 100644
--- a/pkgs/typed-racket-pkgs/typed-racket-test/tests/typed-racket/succeed/make-top-predicate.rkt
+++ b/pkgs/typed-racket-pkgs/typed-racket-test/tests/typed-racket/succeed/make-top-predicate.rkt
@@ -3,6 +3,7 @@
 (make-predicate VectorTop)
 (make-predicate BoxTop)
 (make-predicate ChannelTop)
+(make-predicate Async-ChannelTop)
 (make-predicate HashTableTop)
 (make-predicate MPairTop)
 (make-predicate Thread-CellTop)
diff --git a/pkgs/typed-racket-pkgs/typed-racket-test/tests/typed-racket/succeed/threads-and-async-channels.rkt b/pkgs/typed-racket-pkgs/typed-racket-test/tests/typed-racket/succeed/threads-and-async-channels.rkt
new file mode 100644
index 00000000..6ca6189e
--- /dev/null
+++ b/pkgs/typed-racket-pkgs/typed-racket-test/tests/typed-racket/succeed/threads-and-async-channels.rkt
@@ -0,0 +1,76 @@
+#lang typed/racket
+(require typed/racket/async-channel)
+
+;; same as threads-and-channels.rkt, but with async-channels
+
+(: chan (Async-Channelof Symbol))
+(define chan (make-async-channel))
+
+(define (reader)
+  (thread
+   (lambda ()
+     (let loop : True ((i : Integer 10))
+       (if (= i 0)
+           #t
+           (begin (async-channel-get chan)
+                  (loop (- i 1))))))))
+
+(: writer (Symbol -> Thread))
+(define (writer x)
+  (thread
+   (lambda ()
+     (async-channel-put chan x)
+     (async-channel-put chan x))))
+
+(reader)
+(writer 'a)
+(writer 'b)
+(writer 'c)
+(writer 'd)
+(writer 'e)
+
+
+(define-type JumpingChannel (Rec JumpingChannel (Async-Channelof (Pair JumpingChannel Symbol))))
+(: jump-chan JumpingChannel)
+(define jump-chan (make-async-channel))
+
+(define (jumping-reader)
+  (thread
+   (lambda ()
+     (let loop : True ((i : Integer 3)
+                        (c : JumpingChannel jump-chan))
+       (if (= i 0)
+           #t
+           (loop (- i 1)
+                 (car (async-channel-get c))))))))
+
+(jumping-reader)
+(let ((c2 : JumpingChannel (make-async-channel)))
+  (async-channel-put jump-chan (cons c2 'a))
+  (let ((c3 : JumpingChannel (make-async-channel)))
+    (async-channel-put c2 (cons c3 'b))
+    (let ((c4 : JumpingChannel (make-async-channel)))
+      (async-channel-put c3 (cons c4 'c)))))
+
+
+
+
+(: tc (Thread-Cellof Integer))
+(define tc (make-thread-cell 0))
+
+(thread-cell-set! tc 1)
+
+(thread-wait (thread (lambda ()
+                       (displayln (thread-cell-ref tc))
+                       (thread-cell-set! tc 2)
+                       (displayln (thread-cell-ref tc)))))
+
+(thread-cell-ref tc)
+
+(define blocked-thread
+ (thread (lambda ()
+           (async-channel-get ((inst make-async-channel 'unused))))))
+
+
+(thread-suspend blocked-thread)
+(kill-thread blocked-thread)