Remove async-std default runtime support

Cargo.toml

@@ -24,8 +24,7 @@ log = "^0.4"
 minreq = { version = "2.11.0", features = ["json-using-serde"], optional = true }
 reqwest = { version = "0.12",  features = ["json"], default-features = false, optional = true }
 
-# async runtime
-async-std = { version = "1.13", optional = true }
+# default async runtime
 tokio = { version = "1.40", features = ["time"], optional = true }
 
 [dev-dependencies]
@@ -43,8 +42,6 @@ blocking-https-native = ["blocking", "minreq/https-native"]
 blocking-https-bundled = ["blocking", "minreq/https-bundled"]
 
 tokio = ["dep:tokio", "async"]
-async-std = ["dep:async-std", "async"]
-
 async = ["reqwest", "reqwest/socks"]
 async-https = ["async", "reqwest/default-tls"]
 async-https-native = ["async", "reqwest/native-tls"]

src/lib.rs

@@ -1025,14 +1025,6 @@ mod test {
         assert!(client.is_ok());
     }
 
-    #[cfg(feature = "async-std")]
-    #[test]
-    fn use_async_std_runtime() {
-        let builder = Builder::new("https://blockstream.info/testnet/api");
-        let client = builder.build_async();
-        assert!(client.is_ok());
-    }
-
     #[cfg(not(feature = "tokio"))]
     struct TestRuntime;
 

src/runtime.rs

@@ -12,10 +12,3 @@ impl Runtime for DefaultRuntime {
         tokio::time::sleep(duration).await;
     }
 }
-
-#[cfg(feature = "async-std")]
-impl Runtime for DefaultRuntime {
-    async fn sleep(duration: Duration) {
-        async_std::task::sleep(duration).await;
-    }
-}