add bandwidth workflow

@@ -138,23 +138,23 @@ Bandwidth Test Workflow:
    |  Client    |                    |  Server  |
    +-----+------+                    +-----+----+
          |                                 |
-            |  connect vhost------>    |
-            |  <-----result(success)   |
+         |   connect vhost------------->   |
+         |   <-----------result(success)   |
          |                                 |
-            |  <----call(start play)   |
-            |  result(playing)----->   |
-            |  <-------data(playing)   |
-            |  <-----call(stop play)   |
-            |  result(stopped)----->   |
+         |   <----------call(start play)   |
+         |   result(playing)---------->    |
+         |   <-------------data(playing)   |
+         |   <-----------call(stop play)   |
+         |   result(stopped)---------->    |
          |                                 |
-            |  <-call(start publish)   |
-            |  result(publishing)-->   |
-            |  data(publishing)---->   |
-            |  <--call(stop publish)   |
-            |  result(stopped)(1)-->   |
+         |   <-------call(start publish)   |
+         |   result(publishing)------->    |
+         |   data(publishing)--------->    |
+         |   <--------call(stop publish)   |
+         |   result(stopped)(1)------->    |
          |                                 |
-            |  <--------------report   |
-            |  final(2)------------>   |
+         |   <--------------------report   |
+         |   final(2)----------------->    |
          |           <END>                 |
          
 @see: class SrsBandwidth comments.