@java.lang.Override
  public void writeTo(com.google.protobuf.CodedOutputStream output) throws java.io.IOException {
    if (day_ != com.google.type.DayOfWeek.DAY_OF_WEEK_UNSPECIFIED.getNumber()) {
      output.writeEnum(1, day_);
    }
    if (((bitField0_ & 0x00000001) != 0)) {
      output.writeMessage(2, getStartTime());
    }
    getUnknownFields().writeTo(output);
  }
<pre>
Optional. Start time of the window in UTC.
</pre>

<code>.google.type.TimeOfDay start_time = 2 [(.google.api.field_behavior) = OPTIONAL];</code>
java-valkey/proto-google-cloud-valkey-v1/src/main/java/com/google/cloud/memorystore/v1/WeeklyMaintenanceWindow.java