Swift Data gzip压缩时，通过withUnsafeBytes操作数据时，针对小数据量时，会出现压缩内容，不符合预期的情况。如何解决呢？
例如：
var stream = z_stream()
(self as Data).withUnsafeBytes { (bytes:UnsafePointer<Bytef>) in
stream.next_in = UnsafeMutablePointer<Bytef>(mutating:bytes)
stream.avail_in = uInt((self as Data).count)
}
如何优化改进呢？
let uncompressedDataPointer = UnsafeMutablePointer<Bytef>(mutating: self.bytes.bindMemory(to: Bytef.self, capacity: (self as Data).count))
let uncompressedDataLength = uInt(self.count)
var stream = z_stream()
stream.total_out = 0
stream.avail_in = uInt(uncompressedDataLength)
stream.next_in = uncompressedDataPointer
示例如下：
let string = "Hello你好"
let helloData = string.data(using: .utf8)
let compressData = (helloData as? NSData)?.gzipCompressData()
let uncompressData = compressData?.gzipDataUncompress() as? Data
let resString = String(data: uncompressData ?? Data(), encoding: .utf8)
print("resString:\(resString ?? "")")
