private com.google.protobuf.SingleFieldBuilder<
          org.bwapi.proxy.messages.GameMessages.UpgradeType, org.bwapi.proxy.messages.GameMessages.UpgradeType.Builder, org.bwapi.proxy.messages.GameMessages.UpgradeTypeOrBuilder> 
          getUpgradeTypeFieldBuilder() {
        if (upgradeTypeBuilder_ == null) {
          upgradeTypeBuilder_ = new com.google.protobuf.SingleFieldBuilder<
              org.bwapi.proxy.messages.GameMessages.UpgradeType, org.bwapi.proxy.messages.GameMessages.UpgradeType.Builder, org.bwapi.proxy.messages.GameMessages.UpgradeTypeOrBuilder>(
                  upgradeType_,
                  getParentForChildren(),
                  isClean());
          upgradeType_ = null;
        }
        return upgradeTypeBuilder_;
      }