@java.lang.Override
      public void writeTo(com.google.protobuf.CodedOutputStream output) throws java.io.IOException {
        if (((bitField0_ & 0x00000001) != 0)) {
          output.writeMessage(1, getDescription());
        }
        if (((bitField0_ & 0x00000002) != 0)) {
          output.writeMessage(2, getAttributes());
        }
        getUnknownFields().writeTo(output);
      }
<pre>
A set of attributes on the annotation. You can have up to 4 attributes
per Annotation.
</pre>

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