fn normalize_fee_payer_service_encoding(raw: &[u8]) -> Option<Vec<u8>>Expand description
Rewrites the Tempo fee payer service encoding of a raw transaction into the standard envelope encoding.
Fee payer service clients submit sponsorship requests with a 0x00 placeholder in the fee
payer signature field (and the fee token left empty for the sponsor to fill), which the
standard envelope decoder rejects. The placeholder is rewritten to the standard encoding of
[FEE_PAYER_SIGNATURE_MARKER], preserving the sponsored signing state the sender committed
to. Returns the normalized raw transaction when the input carries the placeholder and None
for any other encoding.