Removed channel at_exit handler.

Author: jdantonio

lib/concurrent/channel/buffer/base.rb

@@ -1,5 +1,4 @@
 require 'concurrent/synchronization/lockable_object'
-require 'concurrent/utility/at_exit'
 
 module Concurrent
   class Channel
@@ -33,7 +32,6 @@ def initialize(*args)
             @capacity = 0
             @buffer = nil
             ns_initialize(*args)
-            AtExit.add(self) { terminate_at_exit }
           end
         end
 
@@ -234,11 +232,6 @@ def ns_full?
         def ns_closed?
           @closed
         end
-
-        # @!visibility private
-        def terminate_at_exit
-          synchronize { self.closed = true }
-        end
       end
     end
   end