public Transaction Sign(ECKeyPair key)
{
var hash = Hash.Blake2B(RlpDataForSignature);
var sig = ECDSASign.SignMessage(hash, key, false);
var sigBytes = sig.ToByteArray();
signature = sigBytes.ToHex(true);
var signer = key.GetRawAddress();
byte[] concatenatedBytes = new byte[52];
Unsafe.CopyBlock(ref concatenatedBytes[0], ref hash[0], (uint)hash.Length);
Unsafe.CopyBlock(ref concatenatedBytes[hash.Length], ref signer[0], (uint)signer.Length);
byte[] txIdBytes = Hash.Blake2B(concatenatedBytes);
id = txIdBytes.ToHex(true);
return(this);
}