@java.lang.Override
    public Builder clear() {
      super.clear();
      bitField0_ = 0;
      projectId_ = "";
      traceId_ = "";
      if (spansBuilder_ == null) {
        spans_ = java.util.Collections.emptyList();
      } else {
        spans_ = null;
        spansBuilder_.clear();
      }
      bitField0_ = (bitField0_ & ~0x00000004);
      return this;
    }
<pre>
A trace describes how long it takes for an application to perform an
operation. It consists of a set of spans, each of which represent a single
timed event within the operation.
</pre>

Protobuf type {@code google.devtools.cloudtrace.v1.Trace}
java-trace/proto-google-cloud-trace-v1/src/main/java/com/google/devtools/cloudtrace/v1/Trace.java