Swift 4 iOS app memory usage

MemoryUsage.swift

/// If an error occurs while getting the amount of memory used, the first returned value in the tuple will be 0.

func getMemoryUsedAndDeviceTotalInMegabytes() -> (Float, Float) {
        
    // https://stackoverflow.com/questions/5887248/ios-app-maximum-memory-budget/19692719#19692719
    // https://stackoverflow.com/questions/27556807/swift-pointer-problems-with-mach-task-basic-info/27559770#27559770
    
    var used_megabytes: Float = 0
    
    let total_bytes = Float(ProcessInfo.processInfo.physicalMemory)
    let total_megabytes = total_bytes / 1024.0 / 1024.0
    
    var info = mach_task_basic_info()
    var count = mach_msg_type_number_t(MemoryLayout<mach_task_basic_info>.size)/4
    
    let kerr: kern_return_t = withUnsafeMutablePointer(to: &info) {
        $0.withMemoryRebound(to: integer_t.self, capacity: 1) {
            task_info(
                mach_task_self_,
                task_flavor_t(MACH_TASK_BASIC_INFO),
                $0,
                &count
            )
        }
    }
    
    if kerr == KERN_SUCCESS {
        let used_bytes: Float = Float(info.resident_size)
        used_megabytes = used_bytes / 1024.0 / 1024.0
    }
    
    return (used_megabytes, total_megabytes)
}