chore: update task queue fiber priority to high (#5722)

TaskQueue is used to process callbacks from the requests.
The hypothesis is that increasing its priority, we will reduce P99 latency
of tasks that are being starved by other fibers.

Signed-off-by: Roman Gershman <[email protected]>

Author: romange

helio

@@ -9,6 +9,8 @@
 #include "base/logging.h"
 
 using namespace std;
+using namespace util::fb2;
+
 namespace dfly {
 
 __thread unsigned TaskQueue::blocked_submitters_ = 0;
@@ -25,7 +27,8 @@ void TaskQueue::Start(std::string_view base_name) {
     CHECK(!fb.IsJoinable());
 
     string name = absl::StrCat(base_name, "/", i);
-    fb = util::fb2::Fiber(name, [this] { queue_.Run(); });
+    fb =
+        Fiber(Fiber::Opts{.priority = FiberPriority::HIGH, .name = name}, [this] { queue_.Run(); });
   }
 }