- Assemble an array of all messages which can be received without
- blocking. Effectively draining the message queue if RMR is started
- in mt-call mode, or draining any waiting TCP buffers. If the
- pass_filter parameter is supplied it is treated as one or more message
- types to accept (pass through). Using the default, an empty list, results
- in messages with any type being captured.
+ Assembles an array of all messages which can be received without blocking
+ (but see the timeout parameter). Effectively drains the message queue if
+ RMR is started in mt-call mode, or draining any waiting TCP buffers. If
+ the pass_filter parameter is supplied, it is treated as one or more
+ message types to accept (pass through). Using the default, an empty list,
+ results in capturing all messages. If the timeout parameter is supplied
+ and is not zero, this call may block up to that number of milliseconds
+ waiting for a message to arrive. Using the default, zero, results in
+ non-blocking no-wait behavior.