feat(BackpressuredArray): Add method to check if items are present in BackpressuredArray

ts/classes.backpressuredarray.ts

@@ -34,6 +34,10 @@ export class BackpressuredArray<T> {
     return this.data.length < this.highWaterMark;
   }
 
+  public checkHasItems(): boolean {
+    return this.data.length > 0;
+  }
+
   waitForSpace(): Promise<void> {
     return new Promise<void>((resolve) => {
       if (this.checkSpaceAvailable()) {