Function encode_transaction 

pub fn encode_transaction(
    transaction: UnvalidatedTransaction<'_>,
    output: &mut [u8],
) -> Result<usize, TransactionEncodeError>

Canonically encodes an admitted unvalidated transaction envelope.

Unknown typed transaction payloads are intentionally not accepted here: callers that need lossless forwarding of unsupported types should carry the original bytes instead of constructing a typed field model this crate cannot validate or re-encode.