closable, fair, leak-avoidant, single-wakeup channel

 A closable, fair, single-wakeup channel that avoids the 0 reader space leak
 that Control.Concurrent.Chan from base suffers from.
 .
 The Chan type from Control.Concurrent.Chan consists of both a read
 and write end combined into a single value. This means there is always at
 least 1 read end for a Chan, which keeps any values written to it alive.
 This is a problem for applications/libraries that want to have a channel
 that can have zero listeners.
 .
 This package provides a library for the Haskell programming language.
 See http://www.haskell.org/ for more information on Haskell.