private static String getPrefix(final String input) {
    final String[] parts = input.split(":", 2);
    return parts.length > 0 ? parts[0] : "";
  }
Read a DNS entry from a String.

@param serialized the serialized form of a DNS entry
@return DNS entry if found
@throws IllegalArgumentException if the record cannot be read
ethereum/p2p/src/main/java/org/hyperledger/besu/ethereum/p2p/discovery/dns/DNSResolver.java