chore: remove itertools from dependencies

It's a small library whose benefits don't overweight the drawbacks.
Any additional dependency crate makes the build slower. But itertools in
particular is harmful because it hides some expensive computations
behind simple tempting to use functions such as `sorted_by`.

Cargo.lock

@@ -808,7 +808,6 @@ dependencies = [
  "futures",
  "indoc",
  "inventory",
- "itertools",
  "lazy_static",
  "libc",
  "linkme",

Cargo.toml

@@ -21,7 +21,6 @@ tempfile = "3"
 thiserror = "1.0"
 indoc = "1.0"
 nix = "0.23.1"
-itertools = "0.10.3"
 base64 = "0.13"
 lazy_static = "1.4"
 uuid = {version = "1.0", features = ["v3"]}

src/discovery.rs

@@ -215,7 +215,6 @@ fn proc_discover<'a>(request: Request, request_to: Address) -> Result<Response,
 
 #[cfg(test)]
 mod tests {
-    use itertools::Itertools;
     use std::collections::{BTreeMap, HashMap, HashSet};
 
     use super::*;
@@ -228,7 +227,7 @@ mod tests {
             instances.into_iter().map(|(k, v)| (k.into(), v)).collect();
         let mut done = HashMap::<Address, Role>::new();
         let len = instances.len();
-        let addrs = instances.keys().cloned().collect_vec();
+        let addrs = instances.keys().cloned().collect::<Vec<_>>();
         let mut pending_requests: HashMap<_, _> = addrs
             .iter()
             .cloned()
@@ -290,8 +289,9 @@ mod tests {
                 ("host3:3", Discovery::new("3", ["host1:1"])),
             ];
             let res = run(instances);
+            let first = res.values().next().unwrap().leader_address();
             assert!(
-                res.values().map(Role::leader_address).all_equal(),
+                res.values().map(Role::leader_address).all(|la| la == first),
                 "multiple leaders: {:#?}",
                 res
             );
@@ -307,8 +307,9 @@ mod tests {
                 ("host3:3", Discovery::new("3", ["host2:2"])),
             ];
             let res = run(instances);
+            let first = res.values().next().unwrap().leader_address();
             assert!(
-                res.values().map(Role::leader_address).all_equal(),
+                res.values().map(Role::leader_address).all(|la| la == first),
                 "multiple leaders: {:#?}",
                 res
             );
@@ -327,8 +328,9 @@ mod tests {
                 ("host3:3", Discovery::new("3", ["host3:3"])),
             ];
             let res = run(instances);
+            let first = res.values().next().unwrap().leader_address();
             assert!(
-                res.values().map(Role::leader_address).all_equal(),
+                res.values().map(Role::leader_address).all(|la| la == first),
                 "multiple leaders: {:#?}",
                 res
             );