The rendering engine will start getting the contents of the requested document from the networking layer. This will usually be done in 8kB chunks.呈現(xiàn)引擎一開始會從網(wǎng)絡(luò)層獲取請求文檔的內(nèi)容，內(nèi)容的大小一般限制在 8000 個塊以內(nèi)。8000個塊是什么意思？