swift3 read binary file.swift

        if let stream:InputStream = InputStream(fileAtPath: "/Users/pebble8888/hoge.txt") {
            var buf:[UInt8] = [UInt8](repeating: 0, count: 16)
            stream.open()
            while true {
                let len = stream.read(&buf, maxLength: buf.count) 
                print("len \(len)")
                for i in 0..<len {
                    print(String(format:"%02x ", buf[i]), terminator: "")
                }
                if len < buf.count {
                    break
                }
            }
            stream.close()
        }

Hello,

I 've trying to write the exact same read data to another file but without any success yet.
Would you mind sharing some code for that too?