in EMASCurl/EMASCurlProtocol.m [835:846]
static size_t write_cb(void *contents, size_t size, size_t nmemb, void *userp) {
EMASCurlProtocol *protocol = (__bridge EMASCurlProtocol *)userp;
NSMutableData *data = [[NSMutableData alloc] initWithBytes:contents length:size * nmemb];
// 只有确认获得已经读取了最后一个响应,接受的数据才视为有效数据
if (protocol.currentResponse.isFinalResponse) {
[protocol.client URLProtocol:protocol didLoadData:data];
}
return size * nmemb;
}