Use atomic boolean instead of synchronized access for state management in AbstractAsyncRequestConsumer / AbstractAsyncResponseConsumer

git-svn-id: https://svn.apache.org/repos/asf/httpcomponents/httpcore/trunk@1631091 13f79535-47bb-0310-9956-ffa450edef68
Do not synchronize methods of BasicAsyncRequestProducer and BasicAsyncResponseProducer

git-svn-id: https://svn.apache.org/repos/asf/httpcomponents/httpcore/trunk@1631092 13f79535-47bb-0310-9956-ffa450edef68