isEntry = (obj) => {
  return obj && obj.id !== undefined &&
    obj.next !== undefined &&
    obj.payload !== undefined &&
    obj.v !== undefined &&
    obj.clock !== undefined &&
    obj.refs !== undefined
}
Checks if an object is an Entry.
@param {module:Log~Entry} obj
@return {boolean}
@memberof module:Log~Entry
@private