message: Small correction in threading model diagram.
diff: @@ -14,10 +14,10 @@ participant "Command Thread" as Command
  end note
  participant "Expensive Thread" as Expensive
  / note over Expensive
  - Thread that is occasionally
  - used for execution of
  - some heavy operations like
  - credential definition creation
  + One of threads from threads pool
  + that is occasionally used for
  + execution of some heavy operations
  + like credential definition creation
  or key derivation
  end note
  