win cover clearing sock_send_blocking when external poll
win cover clearing sock_send_blocking when external poll

Signed-off-by: Andy Green <b471f5a494de34531c9e5a6e15abda71edd49104@linaro.org>

ralight/libwebsockets,ralight/libwebsockets,sartura/libwebsockets,sartura/libwebsockets,dumganhar/libwebsockets,sartura/libwebsockets,sartura/libwebsockets,dumganhar/libwebsockets,ralight/libwebsockets,dumganhar/libwebsockets,sartura/libwebsockets,sartura/libwebsockets,dumganhar/libwebsockets,sartura/libwebsockets,dumganhar/libwebsockets,ralight/libwebsockets,ralight/libwebsockets