Introduced parameter "dispatchIO" in the relevant factories so that
they can be configured by users and connections will be created
taking into account this parameter.
For less configurable connection factories, this parameter is
currently hardcoded to either true or false depending on the case.
For example, ALPN and NPN connections have it to false, since they
don't do any blocking operation in onFillable().
Previously, SCEP was skipping the update of the interestOps in case it
was either input or output shutdown.
Now it always set the interestOps as requested and leaves to the
connection decide what interestOps needs to be set.
Introduced a state machine to handle the various scenarios (ST = selector thread, Tx = pooled thread):
ST: call to SCEP.onSelected() moves from SELECTING -> PENDING.
ST: call to SCEP.updateKey() moves from PENDING -> UPDATING -> SELECTING
T1: call to SCEP.changeInterests() moves (SELECTING | PENDING) -> CHANGING -> SELECTING
The race between ST and T1 to move from PENDING to either UPDATING or CHANGING will be won
by one thread only, which will then perform the call to SelectionKey.setInterestOps().
Preferably, this will be done by ST during an updateKey() call. If updateKey() has already
been invoked, then changeInterests() will perform the call to SelectionKey.setInterestOps().
However, if T1 loses, it still has to perform the key update, so it will spin until ST
moves back to SELECTING.
+ From discussion with Simone, the dispatched fillInterest.onFail()
needs to occur, so that the AbstractConnection.onReadTimeout() can
handle the close conditions needed by SPDY and WebSocket.
The EndPoint close within onIdleExpired is a race condition with
this onReadTimeout desired behavior.
Introduced LeakDetector and utility classes LeakTrackingConnectionPool
and LeakTrackingByteBufferPool to track resource pool leakages.
Fixed ConnectionPool to be more precise in closing connections when
release() cannot recycle the connection.
Fixed a leak in server's HttpConnection in case a request arrives with
the Connection: close header: a ByteBuffer was allocated but never
released.
