public Builder mergeTarget(org.bwapi.proxy.messages.GameMessages.UnitId value) {
        if (targetBuilder_ == null) {
          if (((bitField1_ & 0x00000001) == 0x00000001) &&
              target_ != org.bwapi.proxy.messages.GameMessages.UnitId.getDefaultInstance()) {
            target_ =
              org.bwapi.proxy.messages.GameMessages.UnitId.newBuilder(target_).mergeFrom(value).buildPartial();
          } else {
            target_ = value;
          }
          onChanged();
        } else {
          targetBuilder_.mergeFrom(value);
        }
        bitField1_ |= 0x00000001;
        return this;
      }