async function fromCustomClient(client, options = {}, signal) {
  return GeoTIFF.fromSource(makeCustomSource(client, options), signal);
}
Creates a new GeoTIFF from a custom {@link BaseClient}.
@param {BaseClient} client The client.
@param {object} [options] Additional options to pass to the source.
                          See {@link makeRemoteSource} for details.
@param {AbortSignal} [signal] An AbortSignal that may be signalled if the request is
                              to be aborted
@returns {Promise<GeoTIFF>} The resulting GeoTIFF file.