StackExchange.Redis.Format Double digits question

I am using this function and the result will always be unexpected

double StringIncrement(RedisKey key, double value, CommandFlags flags = CommandFlags.None)

var stringIncrement= StringIncrement("StringIncrement", 2.2) // 2.2000000000000002

So I went to check the problem, it might be double 15 digits
but when outputting 17 digits

var redisValue= (RedisValue)2.2;
var result = redisValue.ToString(); // 2.2000000000000002

"StackExchange.Redis.Format" ToString(double value)

internal static string ToString(double value)
{
    if (double.IsInfinity(value))
    {
        if (double.IsPositiveInfinity(value)) return "+inf";
        if (double.IsNegativeInfinity(value)) return "-inf";
    }
    return value.ToString("G17", NumberFormatInfo.InvariantInfo);  <= this
}

Start with StackExchange.Redis.Format.ToString(double) and the RedisValue conversion shown in the issue, then reproduce the 2.2 case through StringIncrement and RedisValue.ToString. Done means the intended numeric precision is established and the reported unexpected representation is resolved or documented with a verified behavior.