InputStream blocking on close

[SamGinrich]

Seems, that a read on a socket inputstream is not unblocked, when the local socket instance is closed.
Debugging showed that ReliableSocket.shutdownInput(), which notifies the waiting thread, is not called.

Workaround 1) Explicit close on the InputStream

Sequence
ReliableSocket.getInputStream.close();
ReliableSocket.close();
would unblock the input stream, though may run into exception as the closed-state of the socket is not properly synchronized

Workaround 2) Modification of RUDP libary

Added the kernel of RealiableSocket.shutdownInput() w/o the throw statements in the asynchronous part of ReliableSocket.closeImpl()
https://github.com/GermanCoding/RUDP/blob/master/RUDP/src/net/rudp/ReliableSocket.java, line 1718

This behaves stable, though it's not clear, whether functional requirements hold for other close sequences.

[GermanCoding]

Can you send a PR for 2)?

[SamGinrich]

Here is modified method ReliableSocket.closeImpl() [Sorry for layout]

```

/**
* Cleans up and closes the socket.
*/
protected void closeImpl()
{
_nullSegmentTimer.cancel();
_keepAliveTimer.cancel();
_state = CLOSE_WAIT;

	final Thread t = new Thread()
	{
		@Override
		public void run()
		{

			// Sam Ginrich 2024-03, unblocking read on inputstream
			synchronized (_recvQueueLock)
			{
				if (!_shutIn)
				{
					_recvQueueLock.notify();
					_shutIn = true;
				}
			}

			_keepAliveTimer.destroy();
			_nullSegmentTimer.destroy();

			try
			{
				Thread.sleep(_profile.nullSegmentTimeout() * 2);
			}
			catch (final InterruptedException xcp)
			{
				Logger.log(xcp);
			}

			_retransmissionTimer.destroy();
			_cumulativeAckTimer.destroy();

			closeSocket();
			connectionClosed();
		}
	};
	t.setName("ReliableSocket-Closing");
	t.setDaemon(true);
	t.start();
}