n = 6
	} else {
		n = 4
	}
	dst = appendVarInt(dst, n, i)
	dst[first] |= encodeTypeByte(indexing, f.Sensitive)
	return appendHpackString(dst, f.Value)
}

// appendTableSize appends v, as encoded in "Header Table Size Update"
// representation, to dst and returns the extended buffer.
func appendTableSize(dst []byte, v uint32) []byte {
	first := len(dst)
	dst = appendVarInt(dst, 5, uint64(v))
	dst[first] |= 0x20

				return 0, -(i + 1) // overflow
			}
			return x | uint64(b)<<s, i + 1
		}
		x |= uint64(b&0x7f) << s
		s += 7
	}
	return 0, 0
}

// AppendVarint appends the varint-encoded form of x,
// as generated by [PutVarint], to buf and returns the extended buffer.
func AppendVarint(buf []byte, x int64) []byte {
	ux := uint64(x) << 1
	if x < 0 {
		ux = ^ux
	}
	return AppendUvarint(buf, ux)
}

	if x != y {
		t.Errorf("Varint(%d): got %d", x, y)
	}
	if n != m {
		t.Errorf("Varint(%d): got n = %d; want %d", x, m, n)
	}

	buf2 := []byte("prefix")
	buf2 = AppendVarint(buf2, x)
	if string(buf2) != "prefix"+string(buf[:n]) {
		t.Errorf("AppendVarint(%d): got %q, want %q", x, buf2, "prefix"+string(buf[:n]))
	}

	y, err := ReadVarint(bytes.NewReader(buf))
	if err != nil {
		t.Errorf("ReadVarint(%d): %s", x, err)
	}