Fix processQueue concurrent execution resulting in too many concurrent requests

processQueue may be invoked from multiple threads as requests complete or new requests are submitted.
The check of `inProcess.size()` and inProcess.put are not atomic, meaning multiple threads may see capacity then overflow that capacity with new requests.

This fix adds a synchronized block.  A non-blocking ReschedulingOperation solution was also considered, but in theory this function should block for a version short period, making simple synchronization potentially a better option.

Author: jentfoo

client/src/main/java/org/threadly/litesockets/client/http/HTTPClient.java

@@ -370,9 +370,11 @@ public ListenableFuture<HTTPResponseData> requestAsync(final ClientHTTPRequest r
 
   protected void processQueue() {
     //This should be done after we do a .select on the ntse to check for more jobs before it exits.
-    HTTPRequestWrapper hrw;
-    while(maxConcurrent > inProcess.size() && (hrw = queue.poll()) != null) {
-      process(hrw);
+    synchronized (inProcess) {
+      HTTPRequestWrapper hrw;
+      while(maxConcurrent > inProcess.size() && (hrw = queue.poll()) != null) {
+        process(hrw);
+      }
     }
   }