func GoID() int64 {
	g := getg()
	p_goid := (*int64)(unsafe.Pointer(g + goidOffset))
	return *p_goid
}
GoID returns the goroutine id of current goroutine
package gls
import (
	"unsafe"
	"github.com/v2pro/plz/reflect2"
)
var goidOffset uintptr = 128
func init() {
	gType := reflect2.TypeByName("runtime.g").(reflect2.StructType)
	if gType == nil {
		panic("failed to get runtime.g type")
	}
	goidField := gType.FieldByName("goid")
	goidOffset = goidField.Offset()
}