folly async io_uring: bump EVB start time on IoSqeBase completion

Summary:
`EventHandler::libeventCallback()` calls `EventBase::bumpHandlingTime()` which sets the `startTime_` of an EVB loop iteration if it wasn't already set. If no `EventHandler`s are run, then `startTime_` is bumped just before running loop callbacks.

The io_uring based `IoUringBackend` and `AsyncIoUringSocket` do not use `EventHandler`. Thus the `startTime_` of an EVB loop iteration is not being set correctly upon handling the first piece of I/O work via the various `IoSqeBase` types.

Fix this by adding the EventBase to that an IoSqeBase is tied to, and call `EventBase::bumpHandlingTime()` when completing an IoSqeBase i.e. invoking its callback.

Reviewed By: yfeldblum

Differential Revision: D68537153

fbshipit-source-id: 9e991213d69ffa32778e06a0fb447b0514bebba5

Author: spikeh

folly/io/async/IoUringBackend.cpp

@@ -477,6 +477,9 @@ void IoSqeBase::internalCallback(const io_uring_cqe* cqe) noexcept {
   if (!(cqe->flags & IORING_CQE_F_MORE)) {
     inFlight_ = false;
   }
+  if (evb_) {
+    evb_->bumpHandlingTime();
+  }
   if (cancelled_) {
     callbackCancelled(cqe);
   } else {

folly/io/async/IoUringBackend.h

@@ -36,6 +36,7 @@
 #include <folly/Optional.h>
 #include <folly/Range.h>
 #include <folly/io/IOBuf.h>
+#include <folly/io/async/EventBase.h>
 #include <folly/io/async/EventBaseBackendBase.h>
 #include <folly/io/async/IoUringBase.h>
 #include <folly/io/async/Liburing.h>

folly/io/async/IoUringBase.h

@@ -27,6 +27,7 @@ struct io_uring_cqe;
 namespace folly {
 
 class IoUringBackend;
+class EventBase;
 
 struct IoSqeBase
     : boost::intrusive::list_base_hook<
@@ -57,6 +58,7 @@ struct IoSqeBase
   bool inFlight() const { return inFlight_; }
   bool cancelled() const { return cancelled_; }
   void markCancelled() { cancelled_ = true; }
+  void setEventBase(EventBase* evb) { evb_ = evb; }
 
  protected:
   // This is used if you want to prepare this sqe for reuse, but will manage the
@@ -72,6 +74,7 @@ struct IoSqeBase
 
   bool inFlight_ = false;
   bool cancelled_ = false;
+  EventBase* evb_ = nullptr;
   Type type_;
 };