State type of the
downloads API defines different states that a current download can be in.
state property will contain a string taken from the values defined in this type.
Values of this type are strings. Possible values are:
The browser is currently receiving download data from the server.
An error broke the connection with the server.
The download completed successfully.
Note: These string constants will never change, but new constants may be added.
BCD tables only load in the browser
Note: This API is based on Chromium's