public static byte[] serializedOutpoint(String hash, long ix) {
   WireFormat.Writer writer = new WireFormat.Writer();
   writer.writeHash(new Hash(hash));
   writer.writeUint32(ix);
   return writer.toByteArray();
 }
 public void toWire(WireFormat.Writer writer) {
   writer.writeVarBytes(filter);
   writer.writeUint32(hashFunctions);
   writer.writeUint32(tweak);
   writer.writeByte(update.ordinal());
 }