public Builder clearSupplyProvider() {
        if (supplyProviderBuilder_ == null) {
          supplyProvider_ = org.bwapi.proxy.messages.GameMessages.UnitType.getDefaultInstance();
          onChanged();
        } else {
          supplyProviderBuilder_.clear();
        }
        bitField0_ = (bitField0_ & ~0x00000040);
        return this;
      }