GPUArray.init can be very slow

[wtholliday]

[JaapWijnen]

Marking the init method with @inlinable should help here as it seems it can't specialise.
Most methods/computed properties of GPUArray should probably be marked with @inlinable actually

[JaapWijnen]

The copying of the memory here:

Anodize/Sources/AnodizeUtil/GPUArray.swift

Line 24 in 8fa6f8d

let raw = UnsafeMutableRawBufferPointer(start: buffer.contents(), count: buffer.length)

Can probably also be improved by using: https://developer.apple.com/documentation/swift/unsafemutablebufferpointer/update(fromcontentsof:)
instead of the for loop