deserialize method
Interface for intput serialization.
Implementation
@override
void deserialize(SerializableInput input) {
formatId = deserializeString(input);
Uint8List blob = deserializeStringBytes(input);
if (!formatId.startsWith('ecdsa-sha2-')) throw FormatException(formatId);
SerializableInput blobInput = SerializableInput(blob);
r = deserializeMpInt(blobInput);
s = deserializeMpInt(blobInput);
if (!blobInput.done) throw FormatException('${blobInput.offset}');
}