Use only alloc feature from futures-util crate

Author: oblique

Cargo.toml

@@ -27,7 +27,7 @@ async-lock = "1.1.4"
 async-trait = "0.1.38"
 blocking = "0.5.1"
 futures-lite = "0.1.11"
-futures-util = "0.3.5"
+futures-util = { version = "0.3.5", default-features = false, features = ["alloc"] }
 
 [dev-dependencies]
 anyhow = "1.0.32"