encoding/INT

    Integers are encoded as ordinary binary big-endian [encoding/String],
    that has prepended byte indicating is it positive or negative integer.

    Negative integers store positive absolute value, minus one.
    After decoding, their value is subtracted from -1.
    Negative value encoded as 0x02 means: -1 - 0x02 => -3.

    Shortest possible form *must* be used, that means no leading zero
    byte. 0 and -1 values are empty strings, so even they won't have
    leading zero.

    Example representations:

    0                     | 0C 80
    1                     | 0C 81 01
    10                    | 0C 81 0A
    100                   | 0C 01 64
    65536                 | 0C 83 010000
    1000000000000         | 0C 85 E8D4A51000
    18446744073709551615  | 0C 88 FFFFFFFFFFFFFFFF
    18446744073709551616  | 0C 89 010000000000000000
    -18446744073709551616 | 0D 88 FFFFFFFFFFFFFFFF
    -18446744073709551617 | 0D 89 010000000000000000
    -1                    | 0D 80
    -10                   | 0D 81 09
    -100                  | 0D 81 63
    -65536                | 0D 82 FFFF