private static string GenerateRequestId()
{
var bytes = new byte[24];
rng.GetBytes(bytes);
var span = bytes.AsSpan();
var buf = new StringBuilder(36);
var u1 = BitConverter.ToUInt64(span.Slice(0, 8));
var u2 = BitConverter.ToUInt64(span.Slice(8, 8));
var u3 = BitConverter.ToUInt64(span.Slice(16, 8));
Base36.ToBase62(u1, buf);
Base36.ToBase62(u2, buf);
Base36.ToBase62(u3, buf);
return(buf.ToString());
}