style: improve use of std api

- replace get(0) by first()
lint message: accessing first element with `objs.get(0)`
help: for further information visit https://rust-lang.github.io/rust-clippy/rust-1.92.0/index.html#get_first
- use io::Error::other method available since Rust 1.87
lint message: this can be `std::io::Error::other(_)`
help: for further information visit https://rust-lang.github.io/rust-clippy/rust-1.92.0/index.html#io_other_error
- implement From<_> instead of Into<_>
lint message: an implementation of `From` is preferred since it gives you `Into<_>` for free where the reverse isn't true
help: `impl From<Local> for Foreign` is allowed by the orphan rules, for more information see
            https://doc.rust-lang.org/reference/items/implementations.html#trait-implementation-coherence
help: for further information visit https://rust-lang.github.io/rust-clippy/rust-1.92.0/index.html#from_over_into
- use next_back instead of rev + next
lint message: manual backwards iteration
help: for further information visit https://rust-lang.github.io/rust-clippy/rust-1.92.0/index.html#manual_next_back
- use saturating_sub instead of manual implement it
lint message: manual arithmetic check found
help: for further information visit https://rust-lang.github.io/rust-clippy/rust-1.92.0/index.html#implicit_saturating_sub
- add Default implementation for Checksummer
use derived Default ans use it in new, as new set all value to None
lint message: you should consider adding a `Default` implementation for `Checksummer`
help: for further information visit https://rust-lang.github.io/rust-clippy/rust-1.92.0/index.html#new_without_default
- use `any` instead of `find` + `is_some`
lint message: called `is_some()` after searching an `Iterator` with `find`
help: for further information visit https://rust-lang.github.io/rust-clippy/rust-1.92.0/index.html#search_is_some
- replace `and_then` + `Some(_)` with `map`
lint message: using `Option.and_then(|x| Some(y))`, which is more succinctly expressed as `map(|x| y)`
help: for further information visit https://rust-lang.github.io/rust-clippy/rust-1.92.0/index.html#bind_instead_of_map
- replace `skip_while` + `next` with `find`
lint message: called `skip_while(<p>).next()` on an `Iterator`
help: this is more succinctly expressed by calling `.find(!<p>)` instead
help: for further information visit https://rust-lang.github.io/rust-clippy/rust-1.92.0/index.html#skip_while_next
- use `matches!` instead of manual implementation
lint message: match expression looks like `matches!` macro
help: for further information visit https://rust-lang.github.io/rust-clippy/rust-1.92.0/index.html#match_like_matches_macro
- use `keys` and `values methods insteads of iterating and ignoring either the keys or values.
help: for further information visit https://rust-lang.github.io/rust-clippy/rust-1.92.0/index.html#iter_kv_map

src/rpc/layout/helper.rs

@@ -264,13 +264,13 @@ impl LayoutHelper {
 			.versions
 			.iter()
 			.map(|x| x.version)
-			.skip_while(|v| {
-				self.ack_lock
+			.find(|v| {
+				!self
+					.ack_lock
 					.get(v)
 					.map(|x| x.load(Ordering::Relaxed) == 0)
 					.unwrap_or(true)
 			})
-			.next()
 			.unwrap_or(self.inner().current().version);
 		let changed = self.update(|layout| {
 			layout

src/rpc/layout/manager.rs

@@ -116,7 +116,7 @@ impl LayoutManager {
 	pub fn sync_table_until(self: &Arc<Self>, table_name: &'static str, version: u64) {
 		let mut table_sync_version = self.table_sync_version.lock().unwrap();
 		*table_sync_version.get_mut(table_name).unwrap() = version;
-		let sync_until = table_sync_version.iter().map(|(_, v)| *v).min().unwrap();
+		let sync_until = *table_sync_version.values().min().unwrap();
 		drop(table_sync_version);
 
 		let mut layout = self.layout.write().unwrap();

src/rpc/system.rs

@@ -951,13 +951,13 @@ fn get_rpc_public_addr(config: &Config) -> Option<SocketAddr> {
 			let filter_subnet: Option<ipnet::IpNet> = config
 				.rpc_public_addr_subnet
 				.as_ref()
-				.and_then(|filter_subnet_str| match filter_subnet_str.parse::<ipnet::IpNet>() {
+				.map(|filter_subnet_str| match filter_subnet_str.parse::<ipnet::IpNet>() {
 					Ok(filter_subnet) => {
 						let filter_subnet_trunc = filter_subnet.trunc();
 						if filter_subnet_trunc != filter_subnet {
 							warn!("`rpc_public_addr_subnet` changed after applying netmask, continuing with {}", filter_subnet.trunc());
 						}
-						Some(filter_subnet_trunc)
+						filter_subnet_trunc
 					}
 					Err(e) => {
 						panic!(