Use IOSurface

Write directly into a shared memory buffer that can be shared directly
with the compositor and avoids copying bytes when presenting (QuartzCore
was copying stuff before).

This also implements double and triple buffering of the surface, to
avoid creating a bunch of unnecessary buffers. The compositor seems to
sometimes work on two buffers at the same time? A bit unsure why.

The way we wait for the compositor to stop using the buffer(s) is kinda
bad, but that can be resolved later, and shouldn't be a problem for
applications that do proper frame-pacing (which Winit doesn't yet
provide though).

Author: madsmtm

Cargo.toml

@@ -105,6 +105,9 @@ objc2-core-graphics = { version = "0.3.2", default-features = false, features =
 objc2-core-foundation = { version = "0.3.2", default-features = false, features = [
     "std",
     "CFCGTypes",
+    "CFNumber",
+    "CFString",
+    "CFDictionary",
 ] }
 objc2-foundation = { version = "0.3.2", default-features = false, features = [
     "std",
@@ -122,6 +125,14 @@ objc2-quartz-core = { version = "0.3.2", default-features = false, features = [
     "CALayer",
     "CATransaction",
 ] }
+objc2-io-surface = { version = "0.3.2", default-features = false, features = [
+    "std",
+    "libc",
+    "objc2",
+    "objc2-core-foundation",
+    "IOSurfaceRef",
+    "IOSurfaceTypes",
+] }
 
 # Web dependencies.
 [target.'cfg(target_family = "wasm")'.dependencies]