Trivial Description
ArrayPipelineDataConverter : FullMessage will throw on null data if there is more than one message in the pipeline.
This line:
`int nElements = pipelineMessage.Sum(v => v.Data.Length);`
assumes that all "Data" payloads are not null, which may not be the case.
While these payloads are never knowingly constructed as null, we should still protect against this case.