docs: function setbit(key, offset, value, req) {
    var buf = this.getValueBuffer(key, req, true)
      , zeros
      , pos
      , shift
      , byte
      , bit;
    if(buf === undefined) buf = new Buffer('');
    pos = Math.floor(offset / 8);
    bit = pos >= buf.length ? 0 : this.getbit(key, offset, req);
  
    if(pos + 1 >= buf.length) {
      zeros = new Buffer(pos + 1 - buf.length);
      zeros.fill('\u0000');
      buf = Buffer.concat([buf, zeros], buf.length + zeros.length);
    }
  
    shift = 7 - (offset & 0x7);
    byte = buf[pos];
    byte &= ~(1 << shift);
    byte |= ((value & 0x01) << shift);
    buf[pos] = byte;
    this.setKey(key, buf, undefined, undefined, undefined, req);
    return bit;
  }