我无法理解SPDY如何解决HOL阻塞问题。引自:http://chimera.labs.oreilly.com/books/1230000000545/ch02.html#TCP_HOLTounderstandwhythatisthecase,recallthateveryTCPpacketcarriesauniquesequencenumberwhenputonthewire,andthedatamustbepassedtothereceiverin-order(Figure2-8).Ifoneofthepacketsislostenroutetothereceiver,thenal