func WithLogGroup(logGroup string) LoggerOption {
	return func(l *Logger) {
		l.logGroupName = logGroup
	}
}
WithLogGroup sets the log group when ingesting metrics into Cloudwatch Logging Agent.
package emf
import (
	"encoding/json"
	"fmt"
	"io"
	"os"
	"strings"
	"time"
)
type Logger struct {
	out               io.Writer
	timestamp         int64
	defaultContext    Context
	contexts          []*Context
	values            map[string]interface{}
	withoutDimensions bool
	logGroupName      string
}
type Context struct {
	metricDirective MetricDirective
	values          map[string]interface{}
}
type LoggerOption func(l *Logger)
func WithWriter(w io.Writer) LoggerOption {
	return func(l *Logger) {
		l.out = w
	}
}
func WithTimestamp(t time.Time) LoggerOption {
	return func(l *Logger) {
		l.timestamp = t.UnixNano() / int64(time.Millisecond)
	}
}
func WithoutDimensions() LoggerOption {
	return func(l *Logger) {
		l.withoutDimensions = true
	}
}