Get a buffer for an entry.
function entry(object) {
  var buffer;
  switch(object.type) {
    case 'header':
      buffer = this.header(object.version);
      break;
    case 'database':
      buffer = this.database(object.number);
      break;
    case 'key':
      buffer = this.key(object);
      //console.dir(object.type);
      //console.dir(buffer);
      break;
    case 'eof':
      buffer = this.eof();
      break;
  }
  return buffer;
}