All state for this handler. At any point we need to invoke any method outside of this handler, this state should
be stored in a local variable and used after the external call finishes. Failure to do so will cause race
conditions in us using different state before and after the method call specifically if the external call ends
up generating a user generated event and triggering
AbstractHttpConnectionBridge.userEventTriggered(ChannelHandlerContext, Object)
which in turn changes this state.
Issue: https://github.com/Netflix/RxNetty/issues/129