Remove hard dependency on async-std, allow selecting tokio or async-std

Author: praveenperera

Cargo.toml

@@ -22,8 +22,11 @@ bitcoin = { version = "0.32", features = ["serde", "std"], default-features = fa
 hex = { version = "0.2", package = "hex-conservative" }
 log = "^0.4"
 minreq = { version = "2.11.0", features = ["json-using-serde"], optional = true }
-reqwest = { version = "0.11",  features = ["json"], default-features = false, optional = true }
-async-std = { version = "1.13.0", optional = true }
+reqwest = { version = "0.12",  features = ["json"], default-features = false, optional = true }
+
+# async runtime
+async-std = { version = "1.13", optional = true }
+tokio = { version = "1.40", features = ["time"], optional = true }
 
 [dev-dependencies]
 serde_json = "1.0"
@@ -38,7 +41,11 @@ blocking-https = ["blocking", "minreq/https"]
 blocking-https-rustls = ["blocking", "minreq/https-rustls"]
 blocking-https-native = ["blocking", "minreq/https-native"]
 blocking-https-bundled = ["blocking", "minreq/https-bundled"]
-async = ["async-std", "reqwest", "reqwest/socks"]
+
+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"]
 async-https-rustls = ["async", "reqwest/rustls-tls"]

src/async.rs

@@ -11,7 +11,6 @@
 
 //! Esplora by way of `reqwest` HTTP client.
 
-use async_std::task;
 use std::collections::HashMap;
 use std::str::FromStr;
 
@@ -434,7 +433,7 @@ impl AsyncClient {
         loop {
             match self.client.get(url).send().await? {
                 resp if attempts < self.max_retries && is_status_retryable(resp.status()) => {
-                    task::sleep(delay).await;
+                    crate::runtime::sleep(delay).await;
                     attempts += 1;
                     delay *= 2;
                 }

src/lib.rs

@@ -77,6 +77,8 @@ pub mod api;
 pub mod r#async;
 #[cfg(feature = "blocking")]
 pub mod blocking;
+#[cfg(feature = "async")]
+pub mod runtime;
 
 pub use api::*;
 #[cfg(feature = "blocking")]

src/runtime.rs

@@ -0,0 +1,8 @@
+#[cfg(feature = "tokio")]
+pub use tokio::time::sleep;
+
+#[cfg(feature = "async-std")]
+pub use async_std::task::sleep;
+
+#[cfg(not(any(feature = "tokio", feature = "async-std")))]
+compile_error!("Either 'tokio' or 'async-std' feature must be enabled");