UFTP remarks
============

2026-06-19, v5 (and older)
  about cmdClose
    Sessions are initiated by clients (cmdRdRq, cmdWrRq).
    Normal session termination happens on successful transmission (abnormal on timeouts).
    Transmission success can be determind by the receiver only.
    ==> Read sessions must be terminated by the client. Success is gracefully told.
          Packet loss is handled by session timeout.
    ==> Write sessions must be terminated by the server. Success is told by cmdClose.
          Packet loss would keep the client waiting.
          Server should repeat until it receives client's cmdClose (or session timeout).
