func NewHookWithFields(protocol, address, appName string, alwaysSentFields logrus.Fields) (*Hook, error) {
	return NewHookWithFieldsAndPrefix(protocol, address, appName, alwaysSentFields, "")
}
NewHookWithFields creates a new hook to a Logstash instance, which listens on
`protocol`://`address`. alwaysSentFields will be sent with every log entry.
package logrustash
import (
	"net"
	"strings"
	"github.com/sirupsen/logrus"
)
type Hook struct {
	conn             net.Conn
	appName          string
	alwaysSentFields logrus.Fields
	hookOnlyPrefix   string
	TimeFormat       string
}
func NewHook(protocol, address, appName string) (*Hook, error) {
	return NewHookWithFields(protocol, address, appName, make(logrus.Fields))
}
func NewHookWithConn(conn net.Conn, appName string) (*Hook, error) {
	return NewHookWithFieldsAndConn(conn, appName, make(logrus.Fields))
}