It is possible for a task to fetch messages from an SB Pipe
that was created by some other task, and this can happen
easily if someone fetches using ZERO as the pipe ID.

This prevents the consumed message from arriving at its
intended destination.

Note that applications fetching from the wrong Message ID
might notice this issue if they are reporting the receipt
of messages with unexpected Message ID numbers.

Solving this may require some attention to use cases where
a pipe is created by one task, to be used by another.

We may also want to think about the use case where multiple
tasks fetch messages from a single pipe, with the intention
that messages go to one of the several tasks. Is this use
case sufficiently interesting to offset the complexity of the
code required to support it?