找出低进度为何永远得不到专用提示。
swift
enum TransferState {
case waiting
case copying(progress: Double)
case finished
}
func message(for state: TransferState) -> String {
switch state {
case .waiting:
return "Waiting"
case .copying(let progress):
return "Copying \(Int(progress * 100))%"
case .copying(let progress) where progress < 0.1:
return "Starting"
case .finished:
return "Done"
}
}