raw/call.go
func Call(ctx context.Context, ch *tchannel.Channel, hostPort string, serviceName, method string,
	arg2, arg3 []byte) ([]byte, []byte, *tchannel.OutboundCallResponse, error) {

	call, err := ch.BeginCall(ctx, hostPort, serviceName, method, nil)
	if err != nil {
		return nil, nil, nil, err
	}

	return WriteArgs(call, arg2, arg3)
}
func Call(ctx context.Context, ch *tchannel.Channel, hostPort string, serviceName, method string,
	arg2, arg3 []byte) ([]byte, []byte, *tchannel.OutboundCallResponse, error) {

	call, err := ch.BeginCall(ctx, hostPort, serviceName, method, nil)
	if err != nil {
		return nil, nil, nil, err
	}

	return WriteArgs(call, arg2, arg3)
}
// Call makes a call to the given hostPort with the given arguments and returns the response args.