Close a session from the device side and push a closed event.
Open session.
Optionalreason: stringClose reason. Default device disconnected.
false when the session is unknown or already closed.
Push inbound bytes from the device to the session's window.
Open session.
Byte values 0..255.
false when the session is unknown/closed, the bytes are invalid,
or no delivery path to the window exists yet.
Serial mock with device-side controls.