Removed unnecessary end method on Message

Ignore-this: 7e63c572d6eb37a4d8117ff05c043fed

darcs-hash:20130514144009-b22ec-075732c78bb7aa9684a80a9f42bc53e8f5df2779
Only use the Message's lock when necessary

Ignore-this: 8747ada2de012ce2b1ed63bd5f36768

darcs-hash:20130514151221-b22ec-c02ec581d14725c2679885c0bee2186a7917b75e