@Override
    public String toString() {
      return String.format(
          "(typeUrl=%s, outputPrefixType=%s)", typeUrl, outputPrefixToString(outputPrefixType));
    }
Returns the string representation. The exact details are unspecified and subject to change.
java_src/src/main/java/com/google/crypto/tink/internal/LegacyProtoKey.java