Gets a download URL. When the URL is accessed, the FeatureCollection is downloaded in one of several formats.
Returns a download URL or undefined if a callback was specified.
The FeatureCollection instance.
The format of download, one of:
"csv", "json", "geojson", "kml", "kmz" ("json" outputs GeoJSON). If unspecified, defaults to "csv".
Feature property names used to select the attributes to be downloaded. If unspecified, all properties are included.
Name of the file to be downloaded; extension is appended by default. If unspecified, defaults to "table".
An optional callback. If not supplied, the call is made synchronously.