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"""
This means that vortex library should allow the API caller to configure the
message number to be used and Vortex Library should check if the message number
proposed is already "in use", taking "in use" as a message number used without
a reply received.

Because this definition, Vortex Library should allow reusing MSG numbers as
long as they receive a reply.

The change required to fix this must also take care about keeping compatibility
with previous implementations that assume that MSG numbers starts from 0 and
increase by one unit on each send.

The change will also have to add a new function (or functions) to allow the API
caller to configure the message number to use for the next MSG operation.
""""