message: clippy: fix single_match warnings
diff: @@ -135,12 +135,9 @@ impl NextBlock {
  let next_read_lock = self.0
  .read()
  .expect("Failed to acquire write lock in delete queue");
  - match *next_read_lock {
  - InnerNextBlock::Closed(ref block) => {
  + if let InnerNextBlock::Closed(ref block) = *next_read_lock {
  return Some(block.clone());
  }
  - _ => {}
  - }
  }
  let next_block;
  {
  