type eofReader struct {
	buf []byte
}

func (r *eofReader) Read(p []byte) (int, error) {
	read := copy(p, r.buf)
	r.buf = r.buf[read:]

	switch read {
	case 0, len(r.buf):
		// As allowed in the documentation, this will return io.EOF
		// in the same call that consumes the last of the data.
		// https://godoc.org/io#Reader