用Xcode8进行网络请求会出现以下问题

nw_socket_set_common_sockopts setsockopt SO_NOAPNFALLBK failed: [42] Protocol not available, dumping backtrace:
        [x86_64] libnetcore-856.20.4
    0   libsystem_network.dylib             0x000000010ea42682 __nw_create_backtrace_string + 123
    1   libnetwork.dylib                    0x000000010ed1f932 nw_socket_add_input_handler + 3100
    2   libnetwork.dylib                    0x000000010ecfd4f4 nw_endpoint_flow_attach_protocols + 3768
    3   libnetwork.dylib                    0x000000010ecfc511 nw_endpoint_flow_setup_socket + 563
    4   libnetwork.dylib                    0x000000010ecfb270 -[NWConcrete_nw_endpoint_flow startWithHandler:] + 2612
    5   libnetwork.dylib                    0x000000010ed1644d nw_endpoint_handler_path_change + 1261
    6   libnetwork.dylib                    0x000000010ed15e7c nw_endpoint_handler_start + 570
    7   libnetwork.dylib                    0x000000010ed2dae5 nw_endpoint_resolver_start_next_child + 2240
    8   libdispatch.dylib                   0x000000010e7bf980 _dispatch_call_block_and_release + 12
    9   libdispatch.dylib                   0x000000010e7e90cd _dispatch_client_callout + 8
    10  libdispatch.dylib                   0x000000010e7c6e6b _dispatch_queue_serial_drain + 236
    11  libdispatch.dylib                   0x000000010e7c7b9f _dispatch_queue_invoke + 1073
    12  libdispatch.dylib                   0x000000010e7ca3b7 _dispatch_root_queue_drain + 720
    13  libdispatch.dylib                   0x000000010e7ca08b _dispatch_worker_thread3 + 123
    14  libsystem_pthread.dylib             0x000000010eb924de _pthread_wqthread + 1129
    15  libsystem_pthread.dylib             0x000000010eb90341 start_wqthread + 13

解决方法：
进入菜单product -> scheme -> edit scheme -> Run -> Arguments -> Environment Variables 添加环境变量OS_ACTIVITY_MODE 为 disable

屏幕快照 2016-12-06 下午3.39.31.png