Represents the current upload or download progress a API-call.
It contains the number of loaded bytes and, if computable, the total payload size. If the total size cannot be determined, total will be undefined.
total
See MDN: https://developer.mozilla.org/en-US/docs/Web/API/ProgressEvent
Number of bytes currently loaded.
Optional
The total size of the payload, if computable.
Represents the current upload or download progress a API-call.
It contains the number of loaded bytes and, if computable, the total payload size. If the total size cannot be determined,
totalwill be undefined.See MDN: https://developer.mozilla.org/en-US/docs/Web/API/ProgressEvent