A ConnectionQueue listens on a given port number and collects a queue of client connections. In order to handle state changes quickly, a ConnectionQueue has its own process that: (a) tries to keep a socket listening on the port whenever the queue isn't already full of connections and (b) prunes stale connections out of the queue to make room for fresh ones.

	public
	connectionCount destroy getConnectionOrNil getConnectionOrNilLenient isValid

	private	top
	initPortNumber:queueLength: Private! Initialize the receiver to listen on the given port number. Up to queueLength connections will be queued.
	listenLoop Private! This loop is run in a separate process. It will establish up to maxQueueLength connections on the given port.
	oldStyleListenLoop Private! This loop is run in a separate process. It will establish up to maxQueueLength connections on the given port.
	pruneStaleConnections Private! The client may establish a connection and then disconnect while it is still in the connection queue. This method is called periodically to prune such sockets out of the connection queue and make room for fresh connections.

	public	top
	connectionCount Return an estimate of the number of currently queued connections. This is only an estimate since a new connection could be made, or an existing one aborted, at any moment.
	destroy Terminate the listener process and destroy all sockets in my possesion.
	getConnectionOrNil Return a connected socket, or nil if no connection has been established.
	getConnectionOrNilLenient Return a connected socket, or nil if no connection has been established.
	isValid

	instance creation	top
	portNumber:queueLength: