func (container *Container) StderrPipe() (io.ReadCloser, error) {
reader, writer := io.Pipe()
container.stderr.AddWriter(writer, "")
return utils.NewBufReader(reader), nil
}
func (container *Container) StderrLogPipe() io.ReadCloser {
reader, writer := io.Pipe()
container.stderr.AddWriter(writer, "stderr")
return utils.NewBufReader(reader)
}