remove unused dependencies

Cargo.toml

@@ -24,13 +24,8 @@ rustdoc-args = ["--cfg", "feature=\"docs\""]
 default = [
   "std",
   "async-task",
-  "crossbeam-channel",
-  "crossbeam-deque",
-  "crossbeam-queue",
   "kv-log-macro",
   "log",
-  "mio",
-  "mio-uds",
   "num_cpus",
   "pin-project-lite",
   "smol",
@@ -57,17 +52,12 @@ alloc = [
 async-attributes = { version = "1.1.1", optional = true }
 async-task = { version = "3.0.0", optional = true }
 broadcaster = { version = "1.0.0", optional = true }
-crossbeam-channel = { version = "0.4.2", optional = true }
-crossbeam-deque = { version = "0.7.3", optional = true }
-crossbeam-queue = { version = "0.2.0", optional = true }
 crossbeam-utils = { version = "0.7.2", optional = true }
 futures-core = { version = "0.3.4", optional = true, default-features = false }
 futures-io = { version = "0.3.4", optional = true }
 kv-log-macro = { version = "1.0.4", optional = true }
 log = { version = "0.4.8", features = ["kv_unstable"], optional = true }
 memchr = { version = "2.3.3", optional = true }
-mio = { version = "0.6.19", optional = true }
-mio-uds = { version = "0.6.7", optional = true }
 num_cpus = { version = "1.12.0", optional = true }
 once_cell = { version = "1.3.1", optional = true }
 pin-project-lite = { version = "0.1.4", optional = true }