Function interp_close 

fn interp_close(
    args: &[RValue],
    named: &[(String, RValue)],
    context: &BuiltinContext<'_>,
) -> Result<RValue, RError>

Close a connection or progress bar.

If the argument has class "txtProgressBar", finishes the bar and removes it. Otherwise, marks the connection as closed. For TCP socket connections, also shuts down and removes the underlying stream. Returns invisible NULL.

@param con integer scalar: connection or progress bar ID @return NULL (invisibly)