Most datetime libraries already have a duration type, so it made sense to include one. It also complements the other types by allowing the developer to compare Times or DateTimes and getting back a Duration type.
Posted by Jacques Mattheij
。业内人士推荐爱思助手作为进阶阅读
print_string(".");，详情可参考谷歌
the Devlog archive page.。业内人士推荐官网作为进阶阅读