refactor: update gtk/glib, remove glib channels

This is a major refactor which updates GTK, GLib and GTK Layer Shell to their latest versions.

GLib channels, previously used for receiving events on the GLib Main Context thread have been deprecated and a new method for running Futures on the main thread has been added instead. This commit also replaces all the deprecated code with this.

As part of the above, a bug was uncovered related to creating the GLib main context inside the Tokio runtime. Spawning of Tokio tasks has been refactored to fix this.

src/image/provider.rs

@@ -1,4 +1,6 @@
 use crate::desktop_file::get_desktop_icon_name;
+#[cfg(feature = "http")]
+use crate::{glib_recv_mpsc, send_async, spawn};
 use cfg_if::cfg_if;
 use color_eyre::{Help, Report, Result};
 use gtk::cairo::Surface;
@@ -7,13 +9,13 @@ use gtk::gdk_pixbuf::Pixbuf;
 use gtk::prelude::*;
 use gtk::{IconLookupFlags, IconTheme};
 use std::path::{Path, PathBuf};
+#[cfg(feature = "http")]
+use tokio::sync::mpsc;
 use tracing::warn;
 
 cfg_if!(
     if #[cfg(feature = "http")] {
-        use crate::send;
         use gtk::gio::{Cancellable, MemoryInputStream};
-        use tokio::spawn;
         use tracing::error;
     }
 );
@@ -143,18 +145,18 @@ impl<'a> ImageProvider<'a> {
         #[cfg(feature = "http")]
         if let ImageLocation::Remote(url) = &self.location {
             let url = url.clone();
-            let (tx, rx) = glib::MainContext::channel(glib::PRIORITY_DEFAULT);
+            let (tx, mut rx) = mpsc::channel(64);
 
             spawn(async move {
                 let bytes = Self::get_bytes_from_http(url).await;
                 if let Ok(bytes) = bytes {
-                    send!(tx, bytes);
+                    send_async!(tx, bytes);
                 }
             });
 
             {
                 let size = self.size;
-                rx.attach(None, move |bytes| {
+                glib_recv_mpsc!(rx, bytes => {
                     let stream = MemoryInputStream::from_bytes(&bytes);
 
                     let scale = image.scale_factor();
@@ -175,8 +177,6 @@ impl<'a> ImageProvider<'a> {
                         Err(err) => error!("{err:?}"),
                         _ => {}
                     }
-
-                    Continue(false)
                 });
             }
         } else {