ios – 获取“_utf8_nextCharSafeBody”错误

Undefined symbols for architecture x86_64:
      "_utf8_nextCharSafeBody",referenced from:
          _validate_dispatch_data_partial_string in MPWebSocket.o
    ld: symbol(s) not found for architecture x86_64
    clang: error: linker command Failed with exit code 1 (use -v to see invocation)

据我所知,从documentation设置说明中,我已正确添加了框架.这个错误消息似乎不是MixPanel独有的,所以我想知道是什么原因造成这种情况,以及我错误地集成了SDK的哪个方面？