NGX_LOWAT_EVENT   357 event/ngx_event.h #define NGX_LOWAT_EVENT    0
NGX_LOWAT_EVENT   379 event/ngx_event.h #undef  NGX_LOWAT_EVENT
NGX_LOWAT_EVENT   380 event/ngx_event.h #define NGX_LOWAT_EVENT    EV_FLAG1