BlockSpreadEvent

Called when a block spreads based on world conditions.

Use {@link BlockFormEvent} to catch blocks that "randomly" form instead of

actually spread.

Examples:

Mushrooms spreading.
Fire spreading.

If a Block Spread event is cancelled, the block will not spread.

@see BlockFormEvent

当一应条件合适，方块开始向四周蔓延时触发。

如欲监听某些方块“随机”生成的事件，请参见 BlockFormEvent 。本事件在方块蔓延时触发。

本事件触发的情景包括：

蘑菇生长。
火焰蔓延。

如果本事件被取消，则涉事方块不会蔓延。

@see 参见 BlockFormEvent 。

Gets the source block involved in this event.

@return the Block for the source block involved in this event.

该方法用于获取向外蔓延的源头方块。

@return 向外蔓延的源头方块。