All HTTP timing is done by AIHTTPTimeoutPolicy.
Inside LLTextureFetchWorker::doWork when mState == SEND_HTTP_REQ,
mCanUseHTTP is true, throttling is not in effect and mURL is not empty,
mLoaded is set to FALSE, mState is set to WAIT_HTTP_REQ and
LLHTTPClient::request is called that starts the download by curl.
A call back to LLTextureFetchWorker::callbackHttpGet is guaranteed,
which causes mLoaded to be set to TRUE (HTTPGetResponder::completedRaw
calls LLTextureFetchWorker::callbackHttpGet which sets mRequestedSize to -1
(if there was an error) and mLoaded to TRUE).
Being in state WAIT_HTTP_REQ, once mLoaded == TRUE (and mRequestedSize
is -1), the different timeout errors are handled.