Remove use for async-trait and improve docs and feature usage

Cargo.toml

@@ -26,7 +26,6 @@ reqwest = { version = "0.11",  features = ["json"], default-features = false, op
 
 # default async runtime
 tokio = { version = "1.38", features = ["time"], optional = true }
-async-trait = { version = "0.1", optional = true }
 
 [dev-dependencies]
 serde_json = "1.0"
@@ -42,8 +41,8 @@ blocking-https-rustls = ["blocking", "minreq/https-rustls"]
 blocking-https-native = ["blocking", "minreq/https-native"]
 blocking-https-bundled = ["blocking", "minreq/https-bundled"]
 
-tokio = ["dep:tokio", "async"]
-async = ["reqwest", "reqwest/socks", "async-trait"]
+tokio = ["dep:tokio"]
+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

@@ -11,11 +11,9 @@
 
 //! Esplora by way of `reqwest` HTTP client.
 
-use async_trait::async_trait;
 use std::collections::HashMap;
 use std::marker::PhantomData;
 use std::str::FromStr;
-use std::time::Duration;
 
 use bitcoin::consensus::{deserialize, serialize, Decodable, Encodable};
 use bitcoin::hashes::{sha256, Hash};
@@ -43,6 +41,7 @@ pub struct AsyncClient<S = DefaultSleeper> {
     /// Number of times to retry a request
     max_retries: usize,
 
+    /// Marker for the type of sleeper used
     marker: PhantomData<S>,
 }
 
@@ -453,22 +452,19 @@ fn is_status_retryable(status: reqwest::StatusCode) -> bool {
     RETRYABLE_ERROR_CODES.contains(&status.as_u16())
 }
 
-/// Trait that defines the ability to sleep within an async runtime
-#[async_trait]
-pub trait Sleeper {
-    /// Wait until the specified `duration` has elapsed
-    async fn sleep(duration: Duration);
+pub trait Sleeper: 'static {
+    type Sleep: std::future::Future<Output = ()>;
+    fn sleep(dur: std::time::Duration) -> Self::Sleep;
 }
 
-/// Default sleeper. Note this may only be used as a [`Sleeper`] implementation
-/// if the "tokio" feature is enabled.
 #[derive(Debug, Clone, Copy)]
 pub struct DefaultSleeper;
 
 #[cfg(any(test, feature = "tokio"))]
-#[async_trait]
 impl Sleeper for DefaultSleeper {
-    async fn sleep(duration: Duration) {
-        tokio::time::sleep(duration).await;
+    type Sleep = tokio::time::Sleep;
+
+    fn sleep(dur: std::time::Duration) -> Self::Sleep {
+        tokio::time::sleep(dur)
     }
 }

src/lib.rs

@@ -181,7 +181,7 @@ impl Builder {
     }
 
     /// Build an asynchronous client from builder
-    #[cfg(feature = "tokio")]
+    #[cfg(all(feature = "async", feature = "tokio"))]
     pub fn build_async(self) -> Result<AsyncClient, Error> {
         AsyncClient::from_builder(self)
     }
@@ -271,7 +271,6 @@ mod test {
             bitcoind::bitcoincore_rpc::json::AddressType, bitcoind::bitcoincore_rpc::RpcApi,
             electrum_client::ElectrumApi,
         },
-        r#async::DefaultSleeper,
         std::time::Duration,
         tokio::sync::OnceCell,
     };
@@ -330,8 +329,13 @@ mod test {
         let blocking_client = builder.build_blocking();
 
         let builder_async = Builder::new(&format!("http://{}", esplora_url));
+
+        #[cfg(feature = "tokio")]
+        let async_client = builder_async.build_async().unwrap();
+
+        #[cfg(not(feature = "tokio"))]
         let async_client = builder_async
-            .build_async_with_sleeper::<DefaultSleeper>()
+            .build_async_with_sleeper::<r#async::DefaultSleeper>()
             .unwrap();
 
         (blocking_client, async_client)
@@ -1005,7 +1009,7 @@ mod test {
         assert_eq!(tx, tx_async);
     }
 
-    #[cfg(feature = "tokio")]
+    #[cfg(all(feature = "async", feature = "tokio"))]
     #[test]
     fn use_builder_with_tokio_as_normal() {
         let builder = Builder::new("https://blockstream.info/testnet/api");