"async-await" feature

Author: taiki-e

futures-util/Cargo.toml

@@ -25,7 +25,7 @@ nightly = ["futures-core-preview/nightly", "futures-sink-preview/nightly"]
 cfg-target-has-atomic = ["futures-core-preview/cfg-target-has-atomic"]
 never-type = []
 alloc = ["futures-core-preview/alloc", "futures-sink-preview/alloc"]
-async-stream = ["std"]
+async-stream = ["std", "async-await"]
 
 [dependencies]
 futures-core-preview = { path = "../futures-core", version = "=0.3.0-alpha.15", default-features = false }

futures/Cargo.toml

@@ -46,4 +46,4 @@ io-compat = ["compat", "futures-util-preview/io-compat"]
 cfg-target-has-atomic = ["futures-core-preview/cfg-target-has-atomic", "futures-util-preview/cfg-target-has-atomic"]
 never-type = ["futures-util-preview/never-type"]
 alloc = ["futures-core-preview/alloc", "futures-sink-preview/alloc", "futures-util-preview/alloc"]
-async-stream = ["std", "futures-util-preview/async-stream", "futures-async-macro-preview"]
+async-stream = ["std", "async-await", "futures-util-preview/async-stream", "futures-async-macro-preview"]