diskio: drop unnecessary constructor wrapper

Author: djc

src/diskio/immediate.rs

@@ -27,12 +27,6 @@ pub(super) struct ImmediateUnpacker {
 }
 
 impl ImmediateUnpacker {
-    pub(super) fn new() -> Self {
-        Self {
-            ..Default::default()
-        }
-    }
-
     fn deque(&self) -> Box<dyn Iterator<Item = CompletedIo>> {
         let mut guard = self.incremental_state.lock().unwrap();
         // incremental file in progress

src/diskio/mod.rs

@@ -459,7 +459,7 @@ pub(super) fn get_executor<'a>(
     // If this gets lots of use, consider exposing via the config file.
     let threads = effective_thread_count(ram_budget, thread_count);
     match threads {
-        0 | 1 => Box::new(immediate::ImmediateUnpacker::new()),
+        0 | 1 => Box::new(immediate::ImmediateUnpacker::default()),
         n => Box::new(threaded::Threaded::new(n, ram_budget)),
     }
 }