rawToSigned method
Implementation
SignedTransaction rawToSigned(RawTransaction rawTxn) {
final signingMessage = TransactionBuilder.getSigningMessage(rawTxn);
final signature = signingFunction(signingMessage);
final authenticator = TransactionAuthenticatorMultiEd25519(publicKey, signature as MultiEd25519Signature);
return SignedTransaction(rawTxn, authenticator);
}