# PolygonUpdates class

该类主要用以描述Polygon的增删改等更新操作

## Constructors

PolygonUpdates.from (Set <Polygon> previous, Set <Polygon> current)
  通过Polygon的前后更新集合构造一个PolygonUpdates

## Properties

hashCode → int
  The hash code for this object. [...]
  read-only, override
polygonIdsToRemove ↔ Set <String>
  想要删除的polygon的id集合
  read / write
polygonsToAdd ↔ Set <Polygon>
  想要添加的polygon对象集合.
  read / write
polygonsToChange ↔ Set <Polygon>
  想要更新的polygon对象集合
  read / write
runtimeType → Type
  A representation of the runtime type of the object.
  read-only, inherited

## Methods

noSuchMethod (Invocation invocation) → dynamic
  Invoked when a non-existent method or property is accessed. [...]
  inherited
toMap () → Map <String, dynamic>
  转换成可以序列化的map
toString () → String
  Returns a string representation of this object.
  override

## Operators

operator == (Object other) → bool
  The equality operator. [...]
  override