Broadcast message for identified user with ActionCable from non Rails application

I have action cable channel with identified user

class DesktopNotificationsChannel < ApplicationCable::Channel

  def subscribed
    reject and return unless current_user.present?
    logger.add_tags 'ActionCable DesktopNotificationsChannel', current_user.id
    stream_for current_user
  end

  def unsubscribed
    # Any cleanup needed when channel is unsubscribed
  end
end

And i'm connecting this channel from my external application (Desktop application written in C# and I'm using WebSocketSharp library for connections). I can successfully listen all broadcasted messages that sent with,

  DesktopNotificationsChannel.broadcast_to(user, data: 'Some Data' )

But i also want to broadcast message from external application. I've tried various ways to broadcast message for specific user but actioncable ignores the message I'm trying to send;

{
    "command": "message",
    "data": {"status": "current_status"},
    "identifier": { "channel": "DesktopNotificationsChannel"}
}

I figured out i have to add user_id or global_id for user that i want to send message in that json but i couldn't succeed.

I also tried change identifier with rails' broadcaster key like desktop_notifications:xxyyyzz but it also didn't work.

I'm missing something but couldn't figured. How can i send broadcast message for specific user from my non rails application.

I managed to fetch messages by adding stream_from and receive method to my channel. I don't know its proper way to do but it but it's working like this.

class DesktopNotificationsChannel < ApplicationCable::Channel

  def subscribed
    reject and return unless current_user.present?
    logger.add_tags 'ActionCable DesktopNotificationsChannel', current_user.id
    stream_for current_user
    stream_from current_user
  end

  def unsubscribed
    # Any cleanup needed when channel is unsubscribed
  end

  def receive(data)
    DesktopNotificationsChannel.broadcast_to(current_user, data:)
  end
end