  We consider the task of analyzing message-passing programs by observing their
run-time behavior.
  We introduce a purely library-based instrumentation method to trace
communication events during execution. A model of the dependencies among events
can be constructed to identify potential bugs. Compared to the vector clock
method, our approach is much simpler and has in general a significant lower
run-time overhead.
  A further advantage is that we also trace events that could not commit. Thus,
we can infer alternative communications. This provides the user with additional
information to identify potential bugs.
  We have fully implemented our approach in the Go programming language and
provide a number of examples to substantiate our claims.
