@java.lang.Override
    public Builder clear() {
      super.clear();
      bitField0_ = 0;
      spanId_ = 0L;
      kind_ = 0;
      name_ = "";
      startTime_ = null;
      if (startTimeBuilder_ != null) {
        startTimeBuilder_.dispose();
        startTimeBuilder_ = null;
      }
      endTime_ = null;
      if (endTimeBuilder_ != null) {
        endTimeBuilder_.dispose();
        endTimeBuilder_ = null;
      }
      parentSpanId_ = 0L;
      internalGetMutableLabels().clear();
      return this;
    }
<pre>
A span represents a single timed event within a trace. Spans can be nested
and form a trace tree. Often, a trace contains a root span that describes the
end-to-end latency of an operation and, optionally, one or more subspans for
its suboperations. Spans do not need to be contiguous. There may be gaps
between spans in a trace.
</pre>

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