Use message instead of interrupt for Windows

src/Malt.jl

@@ -271,6 +271,13 @@ kill(w::Worker) = Base.kill(w.proc)
 Send an interrupt signal to the worker process. This will interrupt the
 latest request (`remotecall*` or `remote_eval*`) that was sent to the worker.
 """
-interrupt(w::Worker) = Base.kill(w.proc, Base.SIGINT)
+function interrupt(w::Worker)
+    if Sys.iswindows()
+        isrunning(w) || throw(TerminatedWorkerException())
+        _send_msg(w.port, (header=:interrupt))
+    else
+        Base.kill(w.proc, Base.SIGINT)
+    end
+end
 
 end # module

src/worker.jl

@@ -34,8 +34,14 @@ function serve(server::Sockets.TCPServer)
             # Handle request asynchronously
             latest = @async begin
                 msg = deserialize(sock)
-                @debug(msg)
-                handle(Val(msg.header), sock, msg)
+                if get(msg, :header, nothing) === :interrupt
+                    if latest isa Task && !istaskdone(latest)
+                        Base.throwto(latest, InterruptException)
+                    end
+                else
+                    @debug(msg)
+                    handle(Val(msg.header), sock, msg)
+                end
             end
         catch InterruptException
             # Rethrow interrupt in the latest task