public Builder setStackTrace(com.google.devtools.cloudtrace.v2.StackTrace value) {
      if (stackTraceBuilder_ == null) {
        if (value == null) {
          throw new NullPointerException();
        }
        stackTrace_ = value;
      } else {
        stackTraceBuilder_.setMessage(value);
      }
      bitField0_ |= 0x00000080;
      onChanged();
      return this;
    }
<pre>
Stack trace captured at the start of the span.
</pre>

<code>.google.devtools.cloudtrace.v2.StackTrace stack_trace = 8;</code>
java-trace/proto-google-cloud-trace-v2/src/main/java/com/google/devtools/cloudtrace/v2/Span.java