AVSpeechSynthesizer 在 iOS 10上报错

AVSpeechSynthesizer *avSpeecher = [[AVSpeechSynthesizer alloc] init];

iOS 10上使用AVSpeechSynthesizer时会输出错误日志，但avSpeecher 还可以使用

[MobileAssetError:1] Unable to copy asset attributes
Could not get attribute 'LocalURL': Error Domain=MobileAssetError Code=1 "Unable to copy asset attributes" UserInfo={NSDescription=Unable to copy asset attributes}
0x17415b800 Copy matching assets reply: XPC_TYPE_DICTIONARY  <dictionary: 0x17415b800> { count = 2, transaction: 0, voucher = 0x0, contents =
    "Assets" => <data: 0x17427e740>: { length = 1237 bytes, contents = 0x62706c6973743030d4010203040506636458247665727369... }
    "Result" => <int64: 0x174222be0>: 0
}
0x17015bee0 Copy assets attributes reply: XPC_TYPE_DICTIONARY  <dictionary: 0x17015bee0> { count = 1, transaction: 0, voucher = 0x0, contents =
    "Result" => <int64: 0x17022e300>: 1
}

该问题原因未知，待解决