ne_set_request_expect100 — function to enable Expect: 100-continue support
#include <ne_request.h>
void ne_set_request_expect100(ne_request *request, int flag);An extension introduced in the HTTP/1.1 specification was
    the use of the Expect: 100-continue header.
    This header allows an HTTP client to be informed of the expected
    response status before the request message body is sent: a useful
    optimisation for situations where a large message body is to be
    sent.  The ne_set_request_expect100 function
    can be used to enable this feature by passing the
    flag parameter as any non-zero
    integer.
Unfortunately, if this header is sent to a server
    which is not fully compliant with the HTTP/1.1 specification, a
    deadlock occurs resulting in a temporarily "hung" connection.
    neon will recover gracefully from this situation, but only after a
    15 second timeout.  It is highly recommended that this option is
    not enabled unless it is known that the server in use correctly
    implements Expect: 100-continue
    support.