code: function (i) {
  			if (i < 0xfd) {
  				// unsigned char
  				return [i];
  			} else if (i <= 1 << 16) {
  				// unsigned short (LE)
  				return [0xfd, i >>> 8, i & 255];
  			} else if (i <= 1 << 32) {
  				// unsigned int (LE)
  				return [0xfe].concat(Crypto.util.wordsToBytes([i]));
  			} else {
  				// unsigned long long (LE)
  				return [0xff].concat(Crypto.util.wordsToBytes([i >>> 32, i]));
  			}
  		}
docs: Turn an integer into a "var_int".
  
  "var_int" is a variable length integer used by Bitcoin's binary format.
  
  Returns a byte array.