An imperative function that returns all the known information about this collection via an AJAX call.

Returns a collection description whose fields include:

  - features: a list containing metadata about the images in the collection.

  - bands: a dictionary describing the bands of the images in this collection.

  - properties: an optional dictionary containing the collection's metadata properties.

this: imagecollectionImageCollectionThe ImageCollection instance.
callbackFunction, optionalAn optional callback. If not supplied, the call is made synchronously. If supplied, will be called with the first parameter if successful and the second if unsuccessful.