Connection is a String property that contains the value for the HTTP general message header that indicates the options desired for a particular connection. The Connection header value must not be forwarded by a proxy over further connections. 

For HTTP/1.1 applications, Connection may contain the value "close" to indicate that the connection will be closed after completion of the response. HTTP/1.1 applications that do not support persistent connections must include the "close" connection option in every message.

TIdProxyConnectionInfo