private com.google.protobuf.SingleFieldBuilderV3<
              com.google.protobuf.Timestamp,
              com.google.protobuf.Timestamp.Builder,
              com.google.protobuf.TimestampOrBuilder>
          getTimeFieldBuilder() {
        if (timeBuilder_ == null) {
          timeBuilder_ =
              new com.google.protobuf.SingleFieldBuilderV3<
                  com.google.protobuf.Timestamp,
                  com.google.protobuf.Timestamp.Builder,
                  com.google.protobuf.TimestampOrBuilder>(
                  getTime(), getParentForChildren(), isClean());
          time_ = null;
        }
        return timeBuilder_;
      }
<pre>
The timestamp indicating the time the event occurred.
</pre>

<code>.google.protobuf.Timestamp time = 1;</code>
java-trace/proto-google-cloud-trace-v2/src/main/java/com/google/devtools/cloudtrace/v2/Span.java