public Builder mergeBuildUnit(org.bwapi.proxy.messages.GameMessages.UnitId value) {
        if (buildUnitBuilder_ == null) {
          if (((bitField1_ & 0x00000040) == 0x00000040) &&
              buildUnit_ != org.bwapi.proxy.messages.GameMessages.UnitId.getDefaultInstance()) {
            buildUnit_ =
              org.bwapi.proxy.messages.GameMessages.UnitId.newBuilder(buildUnit_).mergeFrom(value).buildPartial();
          } else {
            buildUnit_ = value;
          }
          onChanged();
        } else {
          buildUnitBuilder_.mergeFrom(value);
        }
        bitField1_ |= 0x00000040;
        return this;
      }