Un serialize project search (#2857)

This is the first batch of improvements to current project search. There
are few things we can do better still, but I want to get this out in
next Preview.
Most of the slowness at this point seems to stem from updating UI too
often.

Release Notes:
- Improved project search by making it report results sooner.

---------

Co-authored-by: Julia Risley <julia@zed.dev>

crates/collab/src/tests/integration_tests.rs

@@ -4,7 +4,7 @@ use crate::{
 };
 use call::{room, ActiveCall, ParticipantLocation, Room};
 use client::{User, RECEIVE_TIMEOUT};
-use collections::HashSet;
+use collections::{HashMap, HashSet};
 use editor::{
     test::editor_test_context::EditorTestContext, ConfirmCodeAction, ConfirmCompletion,
     ConfirmRename, Editor, ExcerptRange, MultiBuffer, Redo, Rename, ToggleCodeActions, Undo,
@@ -4821,15 +4821,16 @@ async fn test_project_search(
     let project_b = client_b.build_remote_project(project_id, cx_b).await;
 
     // Perform a search as the guest.
-    let results = project_b
-        .update(cx_b, |project, cx| {
-            project.search(
-                SearchQuery::text("world", false, false, Vec::new(), Vec::new()),
-                cx,
-            )
-        })
-        .await
-        .unwrap();
+    let mut results = HashMap::default();
+    let mut search_rx = project_b.update(cx_b, |project, cx| {
+        project.search(
+            SearchQuery::text("world", false, false, Vec::new(), Vec::new()),
+            cx,
+        )
+    });
+    while let Some((buffer, ranges)) = search_rx.next().await {
+        results.entry(buffer).or_insert(ranges);
+    }
 
     let mut ranges_by_path = results
         .into_iter()

crates/collab/src/tests/randomized_integration_tests.rs

@@ -6,7 +6,7 @@ use crate::{
 use anyhow::{anyhow, Result};
 use call::ActiveCall;
 use client::RECEIVE_TIMEOUT;
-use collections::BTreeMap;
+use collections::{BTreeMap, HashMap};
 use editor::Bias;
 use fs::{repository::GitFileStatus, FakeFs, Fs as _};
 use futures::StreamExt as _;
@@ -722,7 +722,7 @@ async fn apply_client_operation(
                 if detach { "detaching" } else { "awaiting" }
             );
 
-            let search = project.update(cx, |project, cx| {
+            let mut search = project.update(cx, |project, cx| {
                 project.search(
                     SearchQuery::text(query, false, false, Vec::new(), Vec::new()),
                     cx,
@@ -730,15 +730,13 @@ async fn apply_client_operation(
             });
             drop(project);
             let search = cx.background().spawn(async move {
-                search
-                    .await
-                    .map_err(|err| anyhow!("search request failed: {:?}", err))
+                let mut results = HashMap::default();
+                while let Some((buffer, ranges)) = search.next().await {
+                    results.entry(buffer).or_insert(ranges);
+                }
+                results
             });
-            if detach {
-                cx.update(|cx| search.detach_and_log_err(cx));
-            } else {
-                search.await?;
-            }
+            search.await;
         }
 
         ClientOperation::WriteFsEntry {