add utils to detect device io characteristics

Signed-off-by: Jason Volk <jason@zemos.net>

src/core/utils/mod.rs

@@ -36,7 +36,7 @@ pub use self::{
 	rand::{shuffle, string as random_string},
 	stream::{IterStream, ReadyExt, Tools as StreamTools, TryReadyExt},
 	string::{str_from_bytes, string_from_bytes},
-	sys::available_parallelism,
+	sys::compute::parallelism as available_parallelism,
 	time::{now_millis as millis_since_unix_epoch, timepoint_ago, timepoint_from_now},
 };