WaitSet::wait does not wait indefinitely when timeout is None

[Soya-Onishi]

Hi.
I am new to ros2 with rust and tried to run minimal_publisher and minimal_subscriber.
However minimal_subscriber does not work in expect ( no output is displayed ).
After investigation, I found that there are some problems in WaitSet::wait().

Current Behavior
Even if passing None to WaitSet::wait, it does not wait until some messages are passed and return immediately (i.e. non-blocking).

Expected Behavior
Waiting (blocking) indefinitely until some messages are passed.

As described here, timeout_ns should be minus if procedure wants to wait indefinitely, but current implementation make rcl_wait non-blocking function by passing zero.