The number of bytes that have been successfully uploaded so far.
OptionalerrorIf the state is error, returns a JavaScript error of the current task snapshot.
Before the upload completes, contains the metadata sent to the server. After the upload completes, contains the metadata sent back from the server.
The reference that spawned this snapshot's upload task.
The current state of the task.
The task of which this is a snapshot.
The total number of bytes to be uploaded.
Snapshot of a storage task (upload or download).