message: Pass client parameter to ITileLoader's loadAndDecode() and cancel().
  Used to support TileLoader sharing for terrain.
diff: @@ -46,9 +46,10 @@ export interface ITileLoader {
  /**
  * Start loading and/or proceed through the various states of loading of this tile.
  *
  + * @param client - Optional client requesting the load.
  * @returns A promise which resolves the [[TileLoaderState]].
  */
  - loadAndDecode(): Promise<TileLoaderState>;
  + loadAndDecode(client?: any): Promise<TileLoaderState>;
  /**
  * Return the current state in form of a promise. Caller can then wait for the promise to be
  @@ -61,6 +62,8 @@ export interface ITileLoader {
  /**
  * Cancel loading of the [[Tile]].
  * Cancellation token is notified, an internal state is cleaned up.
  + * @param client - Optional client requesting the cancelation. It's expected to match one of
  + * the clients that previously called {@link ITileLoader.loadAndDecode}.
  */
  - cancel(): void;
  + cancel(client?: any): void;
  }
  