Using census 0.4

Cargo.toml

@@ -43,7 +43,7 @@ rust-stemmers = "1.2"
 downcast-rs = { version="1.0" }
 tantivy-query-grammar = { path="./query-grammar" }
 bitpacking = {version="0.8", default-features = false, features=["bitpacker4x"]}
-census = "0.3" 
+census = "0.4"
 fnv = "1.0.6"
 owned-read = "0.4"
 failure = "0.1"

src/indexer/segment_updater.rs

@@ -528,11 +528,7 @@ impl SegmentUpdater {
     /// Obsolete files will eventually be cleaned up
     /// by the directory garbage collector.
     pub fn wait_merging_thread(&self) -> crate::Result<()> {
-        for merge_operation in self.merge_operations.changes_iter() {
-            if merge_operation.is_empty() {
-                break;
-            }
-        }
+        self.merge_operations.wait_until_empty();
         Ok(())
     }
 }