When running master with

./pants

, I’m getting this change automatically:

diff --git a/src/rust/engine/Cargo.lock b/src/rust/engine/Cargo.lock
index 310ba1f86..cb05e4b4e 100644
--- a/src/rust/engine/Cargo.lock
+++ b/src/rust/engine/Cargo.lock
@@ -3126,6 +3126,7 @@ source = "registry+<https://github.com/rust-lang/crates.io-index>"
 dependencies = [
  "bytes 0.5.4 (registry+<https://github.com/rust-lang/crates.io-index>)",
  "fnv 1.0.6 (registry+<https://github.com/rust-lang/crates.io-index>)",
+ "futures-core 0.3.4 (registry+<https://github.com/rust-lang/crates.io-index>)",
  "iovec 0.1.4 (registry+<https://github.com/rust-lang/crates.io-index>)",
  "lazy_static 1.4.0 (registry+<https://github.com/rust-lang/crates.io-index>)",
  "libc 0.2.69 (registry+<https://github.com/rust-lang/crates.io-index>)",