pegasocks 移植到iOS ，访问百度正常，访问YouTube奔溃。

获取了203 commits最新的代码。libevent是最新分支代码。访问百度 https://www.baidu.com正常。访问YouTube https://www.youtube.com正常。

播放YouTube视频会奔溃，比如下面地址。

https://r4---sn-i3b7knzs.googlevideo.com/videoplayback?expire=1635935522&ei=whCCYfafGb-H1d8P3o65GA&ip=194.156.99.67&id=o-AIXCyTRCaW3ebf1mJUWRiems4M9pLoZKboX9-XBIsFBH&itag=18&source=youtube&requiressl=yes&mh=uM&mm=31%2C29&mn=sn-i3b7knzs%2Csn-i3belne6&ms=au%2Crdu&mv=m&mvi=4&pl=25&initcwndbps=545000&vprv=1&mime=video%2Fmp4&ns=tJpZGl_LZuQCH3NUaJL7UJgG&gir=yes&clen=1372314&ratebypass=yes&dur=24.055&lmt=1465824066677745&mt=1635913490&fvip=4&fexp=24001373%2C24007246&c=MWEB&n=folhUdYkaDaDqw&sparams=expire%2Cei%2Cip%2Cid%2Citag%2Csource%2Crequiressl%2Cvprv%2Cmime%2Cns%2Cgir%2Cclen%2Cratebypass%2Cdur%2Clmt&sig=AOq0QJ8wRQIhALPKAmqifPnRdJodJ5EdMcNyPVeAoan00JNgJ0ZXJlf4AiAfd_YAtamovP4jaEPn5y9I3BFuU7bD_GkoYSBPqWC4wg%3D%3D&lsparams=mh%2Cmm%2Cmn%2Cms%2Cmv%2Cmvi%2Cpl%2Cinitcwndbps&lsig=AG3C_xAwRAIgBNBfxdLVmDJHLXeXEwlDLlSqlfvxeU0UPmDza5QBagkCIE_oTTNMaaIWV07gz_D0cHplRqd6b1gTIQOxWSFxlrcv&cpn=uLiMR8Aaz8vf3r0W&cver=2.20211102.01.00&ptk=youtube_none&pltype=contentugc

iOS端主要代码改动如下：

            *(dns_base_ptr) = evdns_base_new(                       \
                (base), EVDNS_BASE_INITIALIZE_NAMESERVERS);     \

改为：

            *(dns_base_ptr) = evdns_base_new(                       \
                (base), EVDNS_BASE_NAMESERVERS_NO_DEFAULT);     \
                evdns_base_nameserver_ip_add(*(dns_base_ptr),"8.8.8.8"); \

奔溃点：

bufferevent.c:718: Assertion bufev_private->refcnt > 0 failed in bufferevent_decref_and_unlock_

bufev_private->refcnt会减小到0.

截屏2021-11-03 下午9 44 56

chux0519 / pegasocks

pegasocks 移植到iOS ，访问百度正常，访问YouTube奔溃。 #32