We introduced SocketRecvBuffer which buffers received bytes. Since
HTTP response header and response body are divided with \r\n, we have
to buffer up several bytes to find this delimiter. We use
SocketRecvBuffer to hold these bytes and only consumes header and
passes SocketRecvBuffer, which may contain head of response body, to
next Command. Since FTPConnection doesn't use SocketCore::peekData(),
we left it as is.
Tatsuhiro Tsujikawa