Move to mpsc, drop crossbeam. Simplify

Cargo.lock

@@ -439,29 +439,6 @@ dependencies = [
  "wasmparser 0.47.0",
 ]
 
-[[package]]
-name = "crossbeam"
-version = "0.7.3"
-source = "registry+https://github.com/rust-lang/crates.io-index"
-checksum = "69323bff1fb41c635347b8ead484a5ca6c3f11914d784170b158d8449ab07f8e"
-dependencies = [
- "cfg-if",
- "crossbeam-channel",
- "crossbeam-deque",
- "crossbeam-epoch",
- "crossbeam-queue",
- "crossbeam-utils 0.7.0",
-]
-
-[[package]]
-name = "crossbeam-channel"
-version = "0.4.0"
-source = "registry+https://github.com/rust-lang/crates.io-index"
-checksum = "acec9a3b0b3559f15aee4f90746c4e5e293b701c0f7d3925d24e01645267b68c"
-dependencies = [
- "crossbeam-utils 0.7.0",
-]
-
 [[package]]
 name = "crossbeam-deque"
 version = "0.7.2"
@@ -2008,7 +1985,6 @@ dependencies = [
  "anyhow",
  "cfg-if",
  "cpu-time",
- "crossbeam",
  "filetime",
  "getrandom",
  "lazy_static",