public static SpanKind forNumber(int value) {
      switch (value) {
        case 0:
          return SPAN_KIND_UNSPECIFIED;
        case 1:
          return RPC_SERVER;
        case 2:
          return RPC_CLIENT;
        default:
          return null;
      }
    }
@param value The numeric wire value of the corresponding enum entry.
@return The enum associated with the given numeric wire value.
java-trace/proto-google-cloud-trace-v1/src/main/java/com/google/devtools/cloudtrace/v1/TraceSpan.java