The previous error path used errors.Wrap(err, "unexpected record type")
inside type-mismatch branches where err was already nil. With
go-faster/errors that produced a wrapError with no cause and no detail,
making the user-visible message "unexpected record type" useless for
diagnostics — there was no way to tell what mtg actually sent.
Switch to errors.Errorf with the actual received byte and a 32-byte
hex peek of the read buffer. Also wrap the read-error path with the
same peek so a partial response is visible.
This is a diagnostic-only change; the parser semantics are unchanged.
Co-Authored-By: Claude Opus 4.7 (1M context) <noreply@anthropic.com>
Igor Artamonov
aab48f0dbe