feat(pool): add a Cache pooling service

Author: seanmonstar

.github/workflows/CI.yml

@@ -119,4 +119,4 @@ jobs:
     steps:
       - uses: actions/checkout@v4
       - uses: dtolnay/rust-toolchain@nightly
-      - run: cargo rustdoc -- --cfg docsrs -D rustdoc::broken-intra-doc-links
+      - run: cargo rustdoc --features full -- --cfg docsrs -D rustdoc::broken-intra-doc-links

Cargo.toml

@@ -76,7 +76,7 @@ full = [
 
 client = ["hyper/client", "tokio/net", "dep:tracing", "dep:futures-channel", "dep:tower-service"]
 client-legacy = ["client", "dep:socket2", "tokio/sync", "dep:libc", "dep:futures-util"]
-client-pool = []
+client-pool = ["dep:futures-util"]
 client-proxy = ["client", "dep:base64", "dep:ipnet", "dep:percent-encoding"]
 client-proxy-system = ["dep:system-configuration", "dep:windows-registry"]