1 2--- 3 Cargo.toml | 1 + 4 1 file changed, 1 insertion(+) 5 6diff --git b/Cargo.toml a/Cargo.toml 7index 1f5472d0..ca63f5b5 100644 8--- b/Cargo.toml 9+++ a/Cargo.toml 10@@ -46,6 +46,7 @@ version = "1.8.0" 11 optional = true 12 13 [dev-dependencies] 14+futures = "0.3.21" 15 16 [features] 17 default = ["std"] 18