fix: app cache and other issues (#5460)

* fixes

* #[serde(untagged)] my BEHATED (still kinda broken)

* remove unused hasContent ref

* clean up code in fetch instance

* ping 3 times for average latency

* fix: pinging to be more accurate

TCP_NODELAY — Set on the TCP stream right after connect, preventing Nagle's algorithm from buffering the small ping packet (could save up to ~40ms)

Instant over Utc::now() — Switched to monotonic std::time::Instant for timing, which is more precise and designed for measuring elapsed time (still using chrono just for the ping magic value)

* delete useFetch util and just use native fetch

* rename worlds until functions for more clarity

* fix lint

* fix cache.rs logic

* make backend ping use both impls

* Add optional timeout to server ping

* fix gallery appearing in nav with no items

* remove EU countries and add EU option for server country

* add uk to europe

---------

Co-authored-by: aecsocket <aecsocket@tutanota.com>

packages/app-lib/src/util/server_ping.rs

@@ -69,7 +69,7 @@ pub async fn get_server_status(
 mod modern {
     use super::ServerStatus;
     use crate::ErrorKind;
-    use chrono::Utc;
+    use std::time::Instant;
     use tokio::io::{AsyncReadExt, AsyncWriteExt};
     use tokio::net::{TcpStream, ToSocketAddrs};
 
@@ -79,6 +79,7 @@ mod modern {
         protocol_version: Option<u32>,
     ) -> crate::Result<ServerStatus> {
         let mut stream = TcpStream::connect(address).await?;
+        stream.set_nodelay(true)?;
         handshake(&mut stream, original_address, protocol_version).await?;
         let mut result = status_body(&mut stream).await?;
         result.ping = ping(&mut stream).await.ok();
@@ -155,9 +156,9 @@ mod modern {
     }
 
     async fn ping(stream: &mut TcpStream) -> crate::Result<i64> {
-        let start_time = Utc::now();
-        let ping_magic = start_time.timestamp_millis();
+        let ping_magic = chrono::Utc::now().timestamp_millis();
 
+        let start_time = Instant::now();
         stream.write_all(&[0x09, 0x01]).await?;
         stream.write_i64(ping_magic).await?;
         stream.flush().await?;
@@ -172,8 +173,7 @@ mod modern {
             .into());
         }
 
-        let response_time = Utc::now();
-        Ok((response_time - start_time).num_milliseconds())
+        Ok(start_time.elapsed().as_millis() as i64)
     }
 
     mod varint {