Robustify ping parser

Add some sort of concurrent parser or recursion to pick up new messages in what the current parser would think is the current messages payload, in the situation of bytes lost in transit.

Also sanity check payload length for fixed-width messages.

Start by locating the current parser and the code that processes the current messages payload. Determine how lost bytes can cause new messages to be missed and where fixed-width payload lengths are validated. Done means the parser recovers from byte loss and rejects payloads with invalid fixed-width lengths, with corresponding coverage added where the project’s parser tests live.

Written by the indexing model from the issue text.