DecodedRpcTransaction
The result of decoding a getTransaction response: the
CompiledTransactionMessage (always with a lifetimeToken carrying
the recent blockhash), the loaded ALT addresses pulled from meta (if
any), and — for 'base64' and 'base58' responses — the wire-format
Transaction.
transaction is omitted for encoding: 'json' responses: the server
has already decompiled the wire format, so there are no message bytes
to round-trip. If you need a re-encodable Transaction, fetch
the response with encoding: 'base64'.