public Builder setStartDate(com.google.type.Date value) {
      if (startDateBuilder_ == null) {
        if (value == null) {
          throw new NullPointerException();
        }
        startDate_ = value;
      } else {
        startDateBuilder_.setMessage(value);
      }
      bitField0_ |= 0x00000002;
      onChanged();
      return this;
    }
<pre>
The date from which report generation should start.
UTC time zone.
</pre>

<code>.google.type.Date start_date = 2;</code>
java-storageinsights/proto-google-cloud-storageinsights-v1/src/main/java/com/google/cloud/storageinsights/v1/FrequencyOptions.java