reset the mw_latency to 350.

@@ -165,8 +165,8 @@ vhost mrw.srs.com {
     # SRS always set mw on, so we just set the latency value.
     # the latency of stream >= mw_latency + mr_latency
     # the value recomment is [300, 1800]
-    # default: 450
-    mw_latency      450;
+    # default: 350
+    mw_latency      350;
 }
 
 # vhost for edge, edge and origin is the same vhost

@@ -95,7 +95,7 @@ CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE SOFTWARE.
 *       2000            150         300
 */
 // the default config of mw.
-#define SRS_PERF_MW_SLEEP 450
+#define SRS_PERF_MW_SLEEP 350
 /**
 * use iovs cache in each msg,
 * for the shared ptr message, we calc once and used for every copy.