date and time in Go

Package time provides functionality for measuring and displaying time.
The calendrical calculations always assume a Gregorian calendar, with no leap seconds. 
```
package main

import (
    "time"
    "fmt"
)

func main() {
    start := time.Now()
    ///operation that takes 20 milliseconds ...
    t := time.Now()
    elapsed := t.Sub(start)
    fmt.Println(elapsed)
}
```