@ApiStatus.Internal
  static <I extends BossBarImplementation> @NotNull I get(final @NotNull BossBar bar, final @NotNull Class<I> type) {
    return BossBarImpl.ImplementationAccessor.get(bar, type);
  }
Gets an implementation, and casts it to {@code type}.

@param bar the bossbar
@param type the implementation type
@param <I> the implementation type
@return a {@code I}
@since 4.12.0
api/src/main/java/net/kyori/adventure/bossbar/BossBarImplementation.java