public final int getNumber() {
          if (this == UNRECOGNIZED) {
            throw new java.lang.IllegalArgumentException(
                "Can't get the number of an unknown enum value.");
          }
          return value;
        }
<pre>
Indicates a received message.
</pre>

<code>RECEIVED = 2;</code>
java-trace/proto-google-cloud-trace-v2/src/main/java/com/google/devtools/cloudtrace/v2/Span.java