std::convert::From
ใใๅใๅฅใฎๅใซๅคๆใใๆนๆณใๆไพใใTrait ใใจใใฐ From<i32> for T ใ ใจ i32 ใ T ใซๅคๆใใใกใฝใใใจใชใ
ใใใๅฎ่ฃ
ใใใจๆ้ป็ใซstd::convert::Intoใใคใพใ้ๆนๅใฎๅคๆใๅฎ่ฃ
ใใใ From<T> for U implies Into<U> for T