remove unused rayon dep from the promise crate

promise/Cargo.toml

@@ -7,4 +7,3 @@ edition = "2018"
 [dependencies]
 failure = "0.1"
 failure_derive = "0.1"
-rayon = "1.0"

promise/src/lib.rs

@@ -31,28 +31,6 @@ impl Executor for Box<dyn Executor> {
     }
 }
 
-/// An executor for spawning futures into the rayon global
-/// thread pool
-#[derive(Clone, Default)]
-pub struct RayonExecutor {}
-
-impl RayonExecutor {
-    pub fn new() -> Self {
-        Self {}
-    }
-}
-
-impl BasicExecutor for RayonExecutor {
-    fn execute(&self, f: SpawnFunc) {
-        rayon::spawn(f);
-    }
-}
-impl Executor for RayonExecutor {
-    fn clone_executor(&self) -> Box<dyn Executor> {
-        Box::new(RayonExecutor::new())
-    }
-}
-
 enum PromiseState<T> {
     Waiting(Arc<Core<T>>),
     Fulfilled,
@@ -436,10 +414,4 @@ mod test {
 
         assert_eq!(f2.wait().unwrap(), 246);
     }
-
-    #[test]
-    fn via_rayon() {
-        let f = Future::with_executor(RayonExecutor::new(), || Ok(true));
-        assert_eq!(f.wait().unwrap(), true);
-    }
 }