[WIP] attempt to shutdown OKHTTP when shutting down ldclient

Author: pkaeding

src/main/java/com/launchdarkly/client/LDClient.java

@@ -377,6 +377,17 @@ public void close() throws IOException {
     if (this.updateProcessor != null) {
       this.updateProcessor.close();
     }
+    if (this.config.httpClient != null) {
+      if (this.config.httpClient.dispatcher() != null && this.config.httpClient.dispatcher().executorService() != null) {
+        this.config.httpClient.dispatcher().executorService().shutdown();
+      }
+      if (this.config.httpClient.connectionPool() != null) {
+        this.config.httpClient.connectionPool().evictAll();
+      }
+      if (this.config.httpClient.cache() != null) {
+        this.config.httpClient.cache().close();
+      }
+    }
   }
 
   /**