Function create_tlas_descriptor 

pub fn create_tlas_descriptor<'a>(
    label: Label<'a>,
) -> CreateTlasDescriptorBuilder<'a, SetLabel<Empty>>

Returns CreateTlasDescriptorBuilder for building wgpu::CreateTlasDescriptor

Set all required fields and any optional fields, then call build().

Builder field setters:

• max_instances Required
• flags Required
• update_mode Required