问鉴于IANA条目是已知的，我如何找到一个特定的日期偏移(白天与标准)？

EN

package main

import (
    "log"
    "time"
)

func main() {
    Chicago, _ := time.LoadLocation("America/Chicago")

    t := time.Date(2019, time.March, 1, 12, 30, 0, 0, Chicago)
    log.Print(t)       // 2019-03-01 12:30:00 -0600 CST
    log.Print(t.UTC()) // 2019-03-01 18:30:00 +0000 UTC
    t = time.Date(2019, time.November, 2, 12, 30, 0, 0, Chicago)
    log.Print(t)       // 2019-11-02 12:30:00 -0500 CDT
    log.Print(t.UTC()) // 2019-11-02 17:30:00 +0000 UTC
}

package main

import (
    "fmt"
    "time"

)

func main() {
    Chicago, _ := time.LoadLocation("America/Chicago")

    cdt, _ := time.ParseInLocation("2006-01-02T15:04:05.999999", "2019-04-30T12:34:00.000", Chicago)


    fmt.Println(cdt)
    fmt.Println(cdt.UTC())

    cst, _ := time.ParseInLocation("2006-01-02T15:04:05.999999", "2017-11-20T13:45:00.000", Chicago)

    fmt.Println(cst)
    fmt.Println(cst.UTC())
}