WIP feat: integrate sharding into pool (6)

Author: abonander

sqlx-core/src/pool/inner.rs

@@ -176,6 +176,7 @@ impl<DB: Database> PoolInner<DB> {
                                 .fuse();
                         }
 
+                        // Try to acquire another connected connection.
                         acquire_connected.set(self.acquire_connected().fuse());
                         continue;
                     }

sqlx-core/src/pool/options.rs

@@ -632,7 +632,7 @@ fn default_shards() -> NonZero<usize> {
     #[cfg(feature = "_rt-async-std")]
     if let Some(val) = std::env::var("ASYNC_STD_THREAD_COUNT")
         .ok()
-        .and_then(|s| s.parse())
+        .and_then(|s| s.parse().ok())
     {
         return val;
     }

sqlx-core/src/rt/rt_async_io/time.rs

@@ -1,10 +1,14 @@
-use std::{future::Future, pin::pin, time::Duration};
+use std::{
+    future::Future,
+    pin::pin,
+    time::{Duration, Instant},
+};
 
 use futures_util::future::{select, Either};
 
 use crate::rt::TimeoutError;
 
-pub fn sleep(duration: Duration) {
+pub async fn sleep(duration: Duration) {
     async_io::Timer::after(duration).await;
 }
 
@@ -13,7 +17,7 @@ pub async fn sleep_until(deadline: Instant) {
 }
 
 pub async fn timeout<F: Future>(duration: Duration, future: F) -> Result<F::Output, TimeoutError> {
-    match select(pin!(future), sleep(duration)).await {
+    match select(pin!(future), pin!(sleep(duration))).await {
         Either::Left((result, _)) => Ok(result),
         Either::Right(_) => Err(TimeoutError),
     }