switch to std::sync::mpsc from crossbeam-channel

Since Rust 1.72, Sender<T> implements Send if T: Send, which lets us use
it instead of crossbeam-channel - one less dependency.

Bumps MSRV to 1.72.

Cargo.toml

@@ -32,7 +32,6 @@ calibright = { version = "0.1", features = ["watch"] }
 chrono = { version = "0.4", default-features = false, features = ["clock", "unstable-locales"] }
 chrono-tz = { version = "0.8", features = ["serde"] }
 clap = { version = "4.0", default-features = false, features = ["std", "derive", "help", "usage"] }
-crossbeam-channel = "0.5"
 dirs = "5.0"
 env_logger = "0.10"
 futures = { version = "0.3", default-features = false }

src/blocks/sound/pulseaudio.rs

@@ -9,8 +9,6 @@ use libpulse_binding::mainloop::standard::{IterateResult, Mainloop};
 use libpulse_binding::proplist::{properties, Proplist};
 use libpulse_binding::volume::{ChannelVolumes, Volume};
 
-use crossbeam_channel::{unbounded, Sender};
-
 use std::cmp::{max, min};
 use std::convert::{TryFrom, TryInto};
 use std::io;
@@ -49,7 +47,7 @@ struct Connection {
 }
 
 struct Client {
-    send_req: Sender<ClientRequest>,
+    send_req: std::sync::mpsc::Sender<ClientRequest>,
     ml_waker: MainloopWaker,
 }
 
@@ -198,7 +196,7 @@ impl Connection {
 
 impl Client {
     fn new() -> Result<Client> {
-        let (send_req, recv_req) = unbounded();
+        let (send_req, recv_req) = std::sync::mpsc::channel();
         let ml_waker = MainloopWaker::new().unwrap();
 
         Connection::spawn("sound_pulseaudio", move |mut connection| {
@@ -238,11 +236,11 @@ impl Client {
                 }
 
                 loop {
+                    use std::sync::mpsc::TryRecvError;
                     let req = match recv_req.try_recv() {
                         Ok(x) => x,
-                        Err(e) if e.is_empty() => break,
-                        Err(e) if e.is_disconnected() => return false,
-                        Err(_) => unreachable!(),
+                        Err(TryRecvError::Empty) => break,
+                        Err(TryRecvError::Disconnected) => return false,
                     };
 
                     use ClientRequest::*;