public Builder setTraces(com.google.devtools.cloudtrace.v1.Traces value) {
      if (tracesBuilder_ == null) {
        if (value == null) {
          throw new NullPointerException();
        }
        traces_ = value;
      } else {
        tracesBuilder_.setMessage(value);
      }
      bitField0_ |= 0x00000002;
      onChanged();
      return this;
    }
<pre>
Required. The body of the message.
</pre>

<code>
.google.devtools.cloudtrace.v1.Traces traces = 2 [(.google.api.field_behavior) = REQUIRED];
</code>
java-trace/proto-google-cloud-trace-v1/src/main/java/com/google/devtools/cloudtrace/v1/PatchTracesRequest.java