NGX_SPDY_CTL_BIT   52 src/http/ngx_http_spdy.c     (!((h) & (uint32_t) NGX_SPDY_CTL_BIT << 31))
NGX_SPDY_CTL_BIT  248 src/http/ngx_http_spdy.h     ((uint32_t) NGX_SPDY_CTL_BIT << 31 | NGX_SPDY_VERSION << 16 | (t))