mnemonicToSeed function
Implementation
Uint8List mnemonicToSeed(String mnemonic, {String passphrase = ""}) {
final pbkdf2 = new PBKDF2(digestAlgorithm: new SHA512Digest());
return pbkdf2.process(
data: Uint8List.fromList(mnemonic.codeUnits), passphrase: passphrase);
}