public Builder setBuildId(com.google.devtools.cloudtrace.v2.TruncatableString value) {
      if (buildIdBuilder_ == null) {
        if (value == null) {
          throw new NullPointerException();
        }
        buildId_ = value;
      } else {
        buildIdBuilder_.setMessage(value);
      }
      bitField0_ |= 0x00000002;
      onChanged();
      return this;
    }
<pre>
A unique identifier for the module, usually a hash of its
contents (up to 128 bytes).
</pre>

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