io_uring: mark callbacks as noexcept

Summary: Rather than forcing the IoUringBackend to deal with exceptions - push it to the callbacks like other async callbacks (eg folly::AsyncTransport)

Reviewed By: praihan, ycking21

Differential Revision: D37954822

fbshipit-source-id: 29c8079e4f8e5a40f6be02cd93e2b0e128804c55

quic/server/QuicServerWorker.h

@@ -482,7 +482,7 @@ class QuicServerWorker : public folly::AsyncUDPSocket::ReadCallback,
   }
 
   // from EventRecvmsgCallback
-  EventRecvmsgCallback::MsgHdr* allocateData() override {
+  EventRecvmsgCallback::MsgHdr* allocateData() noexcept override {
     auto* ret = msgHdr_.release();
     if (!ret) {
       ret = new MsgHdr(this);
@@ -493,7 +493,8 @@ class QuicServerWorker : public folly::AsyncUDPSocket::ReadCallback,
     return ret;
   }
 
-  EventRecvmsgMultishotCallback::Hdr* allocateRecvmsgMultishotData() override {
+  EventRecvmsgMultishotCallback::Hdr* allocateRecvmsgMultishotData() noexcept
+      override {
     return new MultishotHdr(this);
   }