Enable tower-buffer to be able to run in browser environment.

This replaces tokio::spawn by wasm_bindgen_futures::spawn_local
for wasm32 target arch.

tower-buffer/Cargo.toml

@@ -32,6 +32,10 @@ tower-service = "0.3"
 tower-layer = "0.3"
 tokio = { version = "0.2", features = ["rt-core", "sync"] }
 tracing = "0.1.2"
+cfg-if = "1.0.0"
+
+[target.'cfg(target_arch = "wasm32")'.dependencies]
+wasm-bindgen-futures = "0.4.18"
 
 [dev-dependencies]
 tower-test = { version = "0.3", path = "../tower-test" }

tower-buffer/src/service.rs

@@ -49,7 +49,15 @@ where
     {
         let (tx, rx) = mpsc::channel(bound);
         let (handle, worker) = Worker::new(service, rx);
-        tokio::spawn(worker);
+
+        cfg_if::cfg_if! {
+            if #[cfg(not(target_arch = "wasm32"))] {
+                tokio::spawn(worker);
+            } else {
+                wasm_bindgen_futures::spawn_local(worker);
+            }
+        }
+
         Buffer { tx, handle }
     }