Some clients may shutdown the sending side of their TCP
connections, while leaving their receiving sides open. Sometimes,
Squid can not tell the difference between a half-closed and a
fully-closed TCP connection.
By default, Squid will immediately close client connections when
read(2) returns "no more data to read."
Change this option to 'on' and Squid will keep open connections
until a read(2) or write(2) on the socket returns an error.
This may show some benefits for reverse proxies. But if not
it is recommended to leave OFF.