ProxyParams is a
TIdProxyConnectionInfo property that represents information need to allow an intermediate connection (proxy) for the client HTTP request. ProxyParams contains properties that identify the Server address and Port to use for the proxy connection, as well as Username and Passwords to be used in contructing HTTP authorization credentials.
ProxyParams is initialized in the Create constructor, and freed in the Destroy destructor. ProxyParams is updated in SetHeaders using the Header values in the input parameter.