// has been reached.
func MaxBytesReader(w ResponseWriter, r io.ReadCloser, n int64) io.ReadCloser {
	if n < 0 { // Treat negative limits as equivalent to 0.
		n = 0
	}
	return &maxBytesReader{w: w, r: r, i: n, n: n}
}

// MaxBytesError is returned by [MaxBytesReader] when its read limit is exceeded.
type MaxBytesError struct {
	Limit int64
}