maybe also add another feature to solve #7106

We shouldn't force features on users of egui_wgpu that they don't need (in theory someone could use the gl or vulkan backend on macos and might want to disable the metal feature).
Instead you can just enable this feature by adding wgpu = {version = "same as wgpu in egui-wgpu", features = "metal"} to your Cargo.toml. You probably don't even need the features = "metal" since metal is part of the default features of wgpu