different backpressure simulation

Author: ptiurin

test/integration/v2/stream.test.ts

@@ -457,14 +457,16 @@ describe("streams", () => {
             );
           }
 
-          // Simulate backpressure with 1ms delay every 1000 chunks
+          // Simulate backpressure with synchronous delay every 1000 chunks
           if (processedChunks % 1000 === 0) {
-            setTimeout(() => {
-              callback();
-            }, 1);
-          } else {
-            callback();
+            // Create a small synchronous delay using a busy loop
+            // This simulates processing time without breaking pipeline completion
+            const start = Date.now();
+            while (Date.now() - start < 1) {
+              // 1ms busy wait
+            }
           }
+          callback();
         } catch (err) {
           console.error("[DEBUG] Error in output stream:", err);
           callback(err as Error);