Provide return value to test failures when decoding buffers

Change-Id: I0a565fc9cc3b93069be7c01901100e04acf33951
Number of sequence must be unique among pipelines.

TODO: We should be capable of matching outgoing events generated in
a pipeline X with incoming events originated as a result of above
events processed in a pipeline Y. This matching must be done using
seq-numbers.

See part-seqnums.txt

Change-Id: Ibc4c3601c3605e26fbdd6e04fdd81d1e8e93bb31