public Builder mergeStartDate(com.google.type.Date value) {
      if (startDateBuilder_ == null) {
        if (((bitField0_ & 0x00000002) != 0)
            && startDate_ != null
            && startDate_ != com.google.type.Date.getDefaultInstance()) {
          getStartDateBuilder().mergeFrom(value);
        } else {
          startDate_ = value;
        }
      } else {
        startDateBuilder_.mergeFrom(value);
      }
      if (startDate_ != null) {
        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