Add reqwest-blocking feature

BREAKING CHANGE: The `reqwest` feature no longer enables reqwest's
`blocking` feature. Instead, that is controlled by a separate
`reqwest-blocking` flag.

Cargo.toml

@@ -19,15 +19,40 @@ maintenance = { status = "actively-developed" }
 default = ["reqwest", "rustls-tls"]
 pkce-plain = []
 native-tls = ["reqwest/native-tls"]
+reqwest-blocking = ["reqwest/blocking"]
 rustls-tls = ["reqwest/rustls-tls"]
 timing-resistant-secret-traits = []
 
+[[example]]
+name = "github"
+required-features = ["reqwest-blocking"]
+
+[[example]]
+name = "google"
+required-features = ["reqwest-blocking"]
+
+[[example]]
+name = "google_devicecode"
+required-features = ["reqwest-blocking"]
+
+[[example]]
+name = "letterboxd"
+required-features = ["reqwest-blocking"]
+
+[[example]]
+name = "msgraph"
+required-features = ["reqwest-blocking"]
+
+[[example]]
+name = "wunderlist"
+required-features = ["reqwest-blocking"]
+
 [dependencies]
 base64 = "0.13"
 thiserror = "1.0"
 http = "0.2"
 rand = "0.8"
-reqwest = { version = "0.11", optional = true, default-features = false, features = ["blocking"] }
+reqwest = { version = "0.11", optional = true, default-features = false }
 serde = { version = "1.0", features = ["derive"] }
 serde_json = "1.0"
 sha2 = "0.10"

src/lib.rs

@@ -440,7 +440,7 @@ mod introspection;
 
 /// HTTP client backed by the [reqwest](https://crates.io/crates/reqwest) crate.
 /// Requires "reqwest" feature.
-#[cfg(feature = "reqwest")]
+#[cfg(any(feature = "reqwest", feature = "reqwest-blocking"))]
 pub mod reqwest;
 
 /// OAuth 2.0 Token Revocation implementation

src/reqwest.rs

@@ -15,12 +15,12 @@ pub enum Error {
     Io(#[from] std::io::Error),
 }
 
-#[cfg(not(target_arch = "wasm32"))]
+#[cfg(all(feature = "reqwest-blocking", not(target_arch = "wasm32")))]
 pub use blocking::http_client;
 
 pub use async_client::async_http_client;
 
-#[cfg(not(target_arch = "wasm32"))]
+#[cfg(all(feature = "reqwest-blocking", not(target_arch = "wasm32")))]
 mod blocking {
     use crate::reqwest::Error;
     use crate::{HttpRequest, HttpResponse};