The main method in the SocketMuxer where the reading occurs. If
the SocketMuxer requires ExecuteThreads from the main execute
queue it should enqueue a SocketReaderRequest for each desired
thread using Kernel.execute(). These SocketReaderRequests will
call this method which is not expected to return until the thread
is no longer needed.
The number of threads concurrently in processSockets() should not
exceed the value indicated by