diskless replication rdb transfer uses pipe, and writes to sockets form the parent process.

misc:
- handle SSL_has_pending by iterating though these in beforeSleep, and setting timeout of 0 to aeProcessEvents
- fix issue with epoll signaling EPOLLHUP and EPOLLERR only to the write handlers. (needed to detect the rdb pipe was closed)
- add key-load-delay config for testing
- trim connShutdown which is no longer needed
- rioFdsetWrite -> rioFdWrite - simplified since there's no longer need to write to multiple FDs
- don't detect rdb child exited (don't call wait3) until we detect the pipe is closed
- Cleanup bad optimization from rio.c, add another one

src/ae.c

@@ -76,6 +76,7 @@ aeEventLoop *aeCreateEventLoop(int setsize) {
     eventLoop->maxfd = -1;
     eventLoop->beforesleep = NULL;
     eventLoop->aftersleep = NULL;
+    eventLoop->flags = 0;
     if (aeApiCreate(eventLoop) == -1) goto err;
     /* Events with mask == AE_NONE are not set. So let's initialize the
      * vector with it. */
@@ -97,6 +98,14 @@ int aeGetSetSize(aeEventLoop *eventLoop) {
     return eventLoop->setsize;
 }
 
+/* Tells the next iteration/s of the event processing to set timeout of 0. */
+void aeDontWait(aeEventLoop *eventLoop, int noWait) {
+    if (noWait)
+        eventLoop->flags |= AE_DONT_WAIT;
+    else
+        eventLoop->flags &= ~AE_DONT_WAIT;
+}
+
 /* Resize the maximum set size of the event loop.
  * If the requested set size is smaller than the current set size, but
  * there is already a file descriptor in use that is >= the requested
@@ -406,6 +415,11 @@ int aeProcessEvents(aeEventLoop *eventLoop, int flags)
             }
         }
 
+        if (eventLoop->flags & AE_DONT_WAIT) {
+            tv.tv_sec = tv.tv_usec = 0;
+            tvp = &tv;
+        }
+
         /* Call the multiplexing API, will return only on timeout or when
          * some event fires. */
         numevents = aeApiPoll(eventLoop, tvp);