Since HTTP requires that each connection be given a max length, each of these connections are 1GB "long" and are terminated when this limit is reached. Each of these connections is tagged with a client session id. When the RPC server component receives the RPC_IN_DATA and RPC_OUT_DATA with the same client session id, it knows that for any request received on the RPC_IN_DATA connection, it must reply back on the RPC_OUT_DATA connection. That's magic.
