buildAirBattleData = (koukuApi) => {
					const obj = {
						total: koukuApi.api_stage1.api_e_count,
						lost: koukuApi.api_stage1.api_e_lostcount,
						state: koukuApi.api_stage1.api_disp_seiku,
					};
					// api_stage2 can be null, bomber count can also be 0 during air_base_attack
					if(koukuApi.api_stage2) {
						obj.bomber = koukuApi.api_stage2.api_e_count;
					}
					return obj;
				}
Lazy register to KC3Network global listener
@param event - the triggered event name.
@param data - the data object built by Kcsapi handler, {} by default.