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>
The linked span is a parent of the current span.
</pre>

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