Describe your problem

When using descriptor indexing, the number of elements can quickly exceed the default descriptor pool size. First, we should issue a warning, if this happens. Second, the pool size should be dynamically increased, if more descriptors are allocated. Idea to circumvent this issue without loosing flexibility (and possibly getting rid of poolSize altogether) is to use a co-routine generator for descriptor set allocation, which dynamically creates a new pool, if the pool size is exceeded.