From dc17855367eb0ce1ca1fed04538c8970b1c7ec4e Mon Sep 17 00:00:00 2001
From: kevin <wanjunfeng@gmail.com>
Date: Sun, 20 Sep 2020 12:08:30 +0800
Subject: [PATCH] printing context key friendly

---
 core/trace/tracespec/vars.go | 9 +++++++--
 1 file changed, 7 insertions(+), 2 deletions(-)

diff --git a/core/trace/tracespec/vars.go b/core/trace/tracespec/vars.go
index fa9d9dc4..4b935558 100644
--- a/core/trace/tracespec/vars.go
+++ b/core/trace/tracespec/vars.go
@@ -1,7 +1,12 @@
 package tracespec
 
+// TracingKey is tracing key for context
+var TracingKey = contextKey("X-Trace")
+
 // contextKey a type for context key
 type contextKey string
 
-// TracingKey is tracing key for context
-var TracingKey = contextKey("X-Trace")
+// Printing a context will reveal a fair amount of information about it.
+func (c contextKey) String() string {
+	return "trace/tracespec context key " + string(c)
+}