Add back @async, using fibers now.

lib/worker.coffee

@@ -235,10 +235,21 @@ class Worker
       # console.log "LEAVE (#{@timestamp()}): #{@key}"
     @_run()
 
+  # Perform the code block asynchronously, outside the
+  # main fiber. The code block should take a callback
+  # and, when the asynchronous operation is complete,
+  # call it with (error, result). The result is returned
+  # from @async, and the error, if any, is thrown.
+  async: (body) ->
+    body (args...) => @_run(args)
+    [err, result] = @yield()
+    throw err if err
+    result
+
   # Resume the fiber, catching any errors
-  _run: (args...) ->
+  _run: (arg) ->
     try
-      @fiber.run args... if @fiber
+      @fiber.run arg if @fiber
     catch e
       @error e
 

lib/workspace.coffee

@@ -47,7 +47,7 @@ Workspace.mixin = (mixins) ->
   extend_workspace mixins
 
 core_methods = {}
-for method in ['emit', 'keys', 'worker', 'bless', 'all', 'each', 'atomic']
+for method in ['emit', 'keys', 'worker', 'bless', 'all', 'each', 'atomic', 'async']
   core_methods[method] = Worker.prototype[method]
 extend_workspace core_methods
 

test/async_test.coffee

@@ -0,0 +1,18 @@
+redeye_suite = require './support/redeye_suite'
+
+module.exports = redeye_suite
+
+  'async test':
+
+    workers:
+      'test': ->
+        @async (callback) ->
+          setTimeout (-> callback null, 216), 100
+
+    setup: ->
+      @request 'test'
+
+    expect: ->
+      @get 'test', (value) =>
+        @assert.eql value, 216
+        @finish()