message: Protocol spec: Explicitly prohibit overlapping sessions for same file ident
diff: @@ -217,6 +217,15 @@ zero for both the version and the salt.
  All version numbers are non-negative integers strictly less than 2^63.
  +It is an error if the client specifies the same client file identifier for two
  +different sessions that overlap in time. More specifically, it is an error if
  +the client sends two IDENT messages with the same client file identifier in the
  +same network connection unless the second one is sent after the termination of
  +the session associated with the first one. For this purpose, the session is
  +considered terminated from the client's point of view when an [UNBIND](#unbind)
  +message has been sent, or an [UNBOUND](#unbound) message has been received from
  +the server, whichever comes first.
  +
  When the server receives an IDENT message, it will start to accept
  [UPLOAD](#upload) message and it will start sending [DOWNLOAD](#download)
  messages to the client, and continue to do so until an [UNBIND](#unbind) message
  