docs: public static boolean isPubKeyCanonical(byte[] pubkey) {
          if (pubkey[0] == 0x04) {
              // Uncompressed pubkey
              if (pubkey.length != 65)
                  return false;
          } else if (pubkey[0] == 0x02 || pubkey[0] == 0x03) {
              // Compressed pubkey
              if (pubkey.length != 33)
                  return false;
          } else
              return false;
          return true;
      }