Get current memory footprint, most resembling that of memory profiling tools in Xcode

MemoryFootprint.swift

// https://stackoverflow.com/a/57315975
// https://forums.developer.apple.com/thread/105088#357415

func memoryFootprint() -> mach_vm_size_t? {
    // The `TASK_VM_INFO_COUNT` and `TASK_VM_INFO_REV1_COUNT` macros are too
    // complex for the Swift C importer, so we have to define them ourselves.
    let TASK_VM_INFO_COUNT = mach_msg_type_number_t(MemoryLayout<task_vm_info_data_t>.size / MemoryLayout<integer_t>.size)
    let TASK_VM_INFO_REV1_COUNT = mach_msg_type_number_t(MemoryLayout.offset(of: \task_vm_info_data_t.min_address)! / MemoryLayout<integer_t>.size)
    var info = task_vm_info_data_t()
    var count = TASK_VM_INFO_COUNT
    let kr = withUnsafeMutablePointer(to: &info) { infoPtr in
        infoPtr.withMemoryRebound(to: integer_t.self, capacity: Int(count)) { intPtr in
            task_info(mach_task_self_, task_flavor_t(TASK_VM_INFO), intPtr, &count)
        }
    }
    guard
        kr == KERN_SUCCESS,
        count >= TASK_VM_INFO_REV1_COUNT
    else { return nil }
    return info.phys_footprint
}

func formattedMemoryFootprint() -> String {
    let usedBytes: UInt64? = UInt64(self.memoryFootprint() ?? 0)
    let usedMB = Double(usedBytes ?? 0) / 1024 / 1024
    let usedMBAsString: String = "\(usedMB)MB"
    return usedMBAsString
 }