From 45e011b06410abdb69c17f2ac5bfbc22aeed5129 Mon Sep 17 00:00:00 2001
From: Manfred Touron <m@42.am>
Date: Thu, 22 Jun 2017 18:21:13 +0200
Subject: [PATCH] preserve Entry's internal vars when calling Entry.WithFields

This way, it's possible to do things like this:

    trace := log.Trace("test")
    ret, err := handler()
    if err != nil {
        trace = trace.WithFields(...custom fields just in case of error...)
    }
    trace.Stop(&err)
---
 entry.go | 6 ++++--
 1 file changed, 4 insertions(+), 2 deletions(-)

diff --git a/entry.go b/entry.go
index 9f0a5e1..378d2c4 100644
--- a/entry.go
+++ b/entry.go
@@ -37,8 +37,10 @@ func (e *Entry) WithFields(fields Fielder) *Entry {
 	f = append(f, e.fields...)
 	f = append(f, fields.Fields())
 	return &Entry{
-		Logger: e.Logger,
-		fields: f,
+		Logger:  e.Logger,
+		fields:  f,
+		start:   e.start,
+		Message: e.Message,
 	}
 }