title: Flask + gRPC trouble
body: <p>I've got a flask API application running on Win by apache + mod_wsgi plugin.
  I made a grpc service by official tutorials, created grpc server and running it as a win service (by some win service manager, can't find it anymore). As grpc client i used a flask endpoint:</p>
  
  <pre><code>@web.route( '/services/&lt;service_name&gt;', methods=[ 'POST' ] )
  def run_service( service_name ):
      #flask response object, little desinged
      resp = EmptyResp()
      try:
          chan = grpc.insecure_channel( 'my.secret.ip:6066' )
          stub = rpc.gen.services_pb2_grpc.ServicesStub( chan )
          #here just trying to find existed method, they got an Empty messasge, can't find a good solution
          rpcResp = stub.__getattribute__( service_name )( rpc.gen.services_pb2.Empty() )
          #my func to decorate response
          resp.data = ObjResp( rpcResp.state )
      except NameError as NErr:
          print( NErr )
          resp.status_code = 404
          resp.data = ErrResp( 'Cannot get RPC generated files')
      except AttributeError as AErr:
          print( AErr )
          resp.status_code = 404
          resp.data = ErrResp( 'Where is no \'%s\' method or problem with RPC files' % service_name )
      except grpc._channel._InactiveRpcError as ErrConnRPC:
          print( ErrConnRPC )
          resp.status_code = 503
          resp.data = ErrResp( 'Cannot connect with RPC service' )
      finally:
          chan.close()
      return resp
  </code></pre>
  
  <p>So, the problem is that first request to that endpoint is completes with 200 and return of RPC method.
  But further requests to <strong>any endpoint of api</strong> are not responding at all. No HTTP timeout error, no crushes of application at all, no attemts to run a flask or gRPC methods (i used print() for that). Just infinite loading. Repairs only by restarting both gRPC and Apache services.</p>
  
  <p>I cannot find any solution to deploy gRPC servers, somy questions are:
  1) What the reason why 2+ requests are not responding;
  2) What is correct way to deploy gRPC servers on Win?
  3) [Optional] In this row: <code>stub.__getattribute__( service_name )( rpc.gen.services_pb2.Empty() )</code> is there an option to do it better way?</p>