diff --git a/Cargo.toml b/Cargo.toml
index 4b79bba..bf8fbf2 100644
--- a/Cargo.toml
+++ b/Cargo.toml
@@ -45,6 +45,7 @@ version = "1.8.0"
 optional = true
 
 [dev-dependencies]
+futures = "0.3.21"
 
 [features]
 default = ["std"]