Function apr_socket_opt_set 

pub unsafe extern "C" fn apr_socket_opt_set(
    sock: *mut apr_socket_t,
    opt: apr_int32_t,
    on: apr_int32_t,
) -> apr_status_t

Setup socket options for the specified socket @param sock The socket to set up. @param opt The option we would like to configure. One of:

           APR_SO_DEBUG      --  turn on debugging information
           APR_SO_KEEPALIVE  --  keep connections active
           APR_SO_LINGER     --  lingers on close if data is present
           APR_SO_NONBLOCK   --  Turns blocking on/off for socket
                                 When this option is enabled, use
                                 the APR_STATUS_IS_EAGAIN() macro to
                                 see if a send or receive function
                                 could not transfer data without
                                 blocking.
           APR_SO_REUSEADDR  --  The rules used in validating addresses
                                 supplied to bind should allow reuse
                                 of local addresses.
           APR_SO_SNDBUF     --  Set the SendBufferSize
           APR_SO_RCVBUF     --  Set the ReceiveBufferSize
           APR_SO_FREEBIND   --  Allow binding to non-local IP address.

@param on Value for the option.