Reset the connection when the channel closes

autoload/vimspector/internal/job.vim

@@ -51,6 +51,7 @@ endfunction
 
 function! s:_OnClose( channel ) abort
   echom "Channel closed"
+  _vimspector_session.OnChannelClosed()
 endfunction
 
 function! s:_Send( msg ) abort

python3/vimspector/debug_session.py

@@ -128,6 +128,9 @@ class DebugSession( object ):
   def OnChannelData( self, data ):
     self._connection.OnData( data )
 
+  def OnChannelClosed( self ):
+    self._connection = None
+
   def Stop( self ):
     self._StopDebugAdapter()