sign method
Returns 65 bytes: r (32) + s (32) + v (1).
Implementation
Uint8List sign(SecretKey key) {
final hash = signingHash();
final sig = RecoverableEcdsaSig.sign(hash, key.bytes);
final out = Uint8List(65);
out.setRange(0, 64, sig.bytes);
out[64] = sig.recId + 27;
return out;
}