sequenceDiagram
  Alice->>Bob: Hello
  Bob->>Charlie: Forward
  Charlie-->>Bob: Reply
  Bob-->>Alice: Done
---
 +-------+   +-----+    +---------+   
 | Alice |   | Bob |    | Charlie |   
 +-------+   +-----+    +---------+   
     |          |            |        
     |  Hello   |            |        
     |---------->            |        
     |          |            |        
     |          |  Forward   |        
     |          |------------>        
     |          |            |        
     |          |   Reply    |        
     |          <............|        
     |          |            |        
     |  Done    |            |        
     <..........|            |        
     |          |            |        
 +-------+   +-----+    +---------+   
 | Alice |   | Bob |    | Charlie |   
 +-------+   +-----+    +---------+   
