We do not want (temporary network) errors to terminate the feature subscriptions, so we report errors on a separate stream.
An Observable of found Features. Each event on the stream corresponds to a mouse event. The data is an array of Features, as a click can hit several features at once. (Or an empty array if nothing was hit).
Sets the source of the mouse events which trigger fetching feature info.
Sets the source to fetch features from.
Converts mouse events (typically clicks) to Features by querying GetFeatureInfo for the given source.