Read an NSInputStream into a String

NSInputStream+String.swift

extension NSInputStream  
{
    public func readString(bufferSize: Int = 4096) -> String {
        guard let data = NSMutableData(capacity: bufferSize) else { return "" }
        let buffer = UnsafeMutablePointer<UInt8>.alloc(bufferSize)

        var bytesRead = 0
        repeat {
            bytesRead = read(buffer, maxLength: bufferSize)
            data.appendBytes(buffer, length: bytesRead)
        } while bytesRead == bufferSize

        let string = String(data: data, encoding: NSUTF8StringEncoding)

        return string ?? ""
    }
}