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# countOfBytesReceived

The number of bytes that the task has received from the server in the response body.

```
var countOfBytesReceived: Int64 { get }
```

## Discussion

To be notified when this value changes, implement the [`urlSession(_:dataTask:didReceive:)`](/documentation/Foundation/URLSessionDataDelegate/urlSession(_:dataTask:didReceive:)) delegate method (for data and upload tasks) or the [`urlSession(_:downloadTask:didWriteData:totalBytesWritten:totalBytesExpectedToWrite:)`](/documentation/Foundation/URLSessionDownloadDelegate/urlSession(_:downloadTask:didWriteData:totalBytesWritten:totalBytesExpectedToWrite:)) method (for download tasks).

---

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