fix(sflow): XDR must be 4-byte-aligned

[bewing]

sFlow text fields must account for padding bytes when reading the buffer.

ref: https://datatracker.ietf.org/doc/html/rfc4506#section-3
ref: https://datatracker.ietf.org/doc/html/rfc4506#section-4.11

[lspgn]

Thank you! I think this may be integrated into #480 but will have a look

[bewing]

Thank you! I think this may be integrated into #480 but will have a look

That does appear to be a fix - apologies for not noticing it in the queue.

Curious if the multi-modulus from #480 or the negative & 3 is more readable.