Perhaps we'll use relm4 for audio?

Cargo.lock

@@ -241,7 +241,8 @@ dependencies = [
  "gtk4",
  "libcosmic-widgets",
  "once_cell",
- "relm4-macros 0.4.2",
+ "pulsectl-rs",
+ "relm4",
  "tokio",
 ]
 
@@ -1013,6 +1014,33 @@ dependencies = [
  "winapi",
 ]
 
+[[package]]
+name = "libpulse-binding"
+version = "2.26.0"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "17be42160017e0ae993c03bfdab4ecb6f82ce3f8d515bd8da8fdf18d10703663"
+dependencies = [
+ "bitflags",
+ "libc",
+ "libpulse-sys",
+ "num-derive",
+ "num-traits",
+ "winapi",
+]
+
+[[package]]
+name = "libpulse-sys"
+version = "1.19.3"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "991e6bd0efe2a36e6534e136e7996925e4c1a8e35b7807fe533f2beffff27c30"
+dependencies = [
+ "libc",
+ "num-derive",
+ "num-traits",
+ "pkg-config",
+ "winapi",
+]
+
 [[package]]
 name = "lock_api"
 version = "0.4.6"
@@ -1123,6 +1151,17 @@ dependencies = [
  "winapi",
 ]
 
+[[package]]
+name = "num-derive"
+version = "0.3.3"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "876a53fff98e03a936a674b29568b0e605f06b29372c2489ff4de23f1949743d"
+dependencies = [
+ "proc-macro2",
+ "quote",
+ "syn",
+]
+
 [[package]]
 name = "num-integer"
 version = "0.1.44"
@@ -1378,6 +1417,15 @@ dependencies = [
  "libc",
 ]
 
+[[package]]
+name = "pulsectl-rs"
+version = "0.3.2"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "06a988bceed1981b2c5fc4a3da0e4e073fdaff8e6bd022b089f54bc573dc3cfc"
+dependencies = [
+ "libpulse-binding",
+]
+
 [[package]]
 name = "quote"
 version = "1.0.15"
@@ -1456,6 +1504,7 @@ dependencies = [
  "gtk4",
  "log",
  "once_cell",
+ "relm4-macros 0.4.1",
  "tokio",
 ]
 

applets/cosmic-applet-audio/Cargo.toml

@@ -7,7 +7,8 @@ license = "LGPL-3.0-or-later"
 [dependencies]
 futures-util = "0.3.21"
 gtk4 = "0.4.6"
-once_cell = "1.10.0"
-relm4-macros = "0.4.2"
-tokio = { version = "1.17.0", features = ["full"] }
 libcosmic-widgets = { git = "https://github.com/pop-os/libcosmic", branch = "lucy/widgets" }
+once_cell = "1.10.0"
+pulsectl-rs = "0.3.2"
+relm4 = { git = "https://github.com/AaronErhardt/relm4", branch = "new-approach", features = ["macros"] }
+tokio = { version = "1.17.0", features = ["full"] }

applets/cosmic-applet-audio/src/main.rs

@@ -1,3 +1,13 @@
+// SPDX-License-Identifier: LGPL-3.0-or-later
+
+#[macro_use]
+extern crate relm4;
+
+use once_cell::sync::Lazy;
+use tokio::runtime::Runtime;
+
+static RT: Lazy<Runtime> = Lazy::new(|| Runtime::new().expect("failed to build tokio runtime"));
+
 fn main() {
     println!("Hello, world!");
 }