@java.lang.Override
  public void writeTo(com.google.protobuf.CodedOutputStream output) throws java.io.IOException {
    if (!com.google.protobuf.GeneratedMessageV3.isStringEmpty(name_)) {
      com.google.protobuf.GeneratedMessageV3.writeString(output, 1, name_);
    }
    for (int i = 0; i < spans_.size(); i++) {
      output.writeMessage(2, spans_.get(i));
    }
    getUnknownFields().writeTo(output);
  }
<pre>
Required. A list of new spans. The span names must not match existing
spans, otherwise the results are undefined.
</pre>

<code>
repeated .google.devtools.cloudtrace.v2.Span spans = 2 [(.google.api.field_behavior) = REQUIRED];
</code>
java-trace/proto-google-cloud-trace-v2/src/main/java/com/google/devtools/cloudtrace/v2/BatchWriteSpansRequest.java