@java.lang.Override
    public Builder clearField(com.google.protobuf.Descriptors.FieldDescriptor field) {
      return super.clearField(field);
    }
<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