fix: skip headers capitalization

http/client/transport_traces.go

@@ -2,6 +2,7 @@ package client
 
 import (
 	"net/http"
+	"net/textproto"
 	"strings"
 
 	"go.opentelemetry.io/otel/attribute"
@@ -46,7 +47,8 @@ func newTransportTraces(tracesOpts *TransportTracesOptions, tracer trace.Tracer,
 	if len(tracesOpts.SkipHeaders) > 0 {
 		sh = make(map[string]bool, len(tracesOpts.SkipHeaders))
 		for _, v := range tracesOpts.SkipHeaders {
-			sh[v] = true
+			canonical := textproto.CanonicalMIMEHeaderKey(v)
+			sh[canonical] = true
 		}
 	}
 	return &transportTraces{

http/server/server.go

@@ -4,6 +4,7 @@ import (
 	"context"
 	"net"
 	"net/http"
+	"net/textproto"
 
 	"go.opentelemetry.io/otel/attribute"
 	"go.opentelemetry.io/otel/propagation"
@@ -93,7 +94,8 @@ func NewTrackingHandlerWithTrustedProxies(next http.Handler, trustedProxies []st
 	if len(gCfg.SkipHeaders) > 0 {
 		sh = make(map[string]bool, len(gCfg.SkipHeaders))
 		for _, v := range gCfg.SkipHeaders {
-			sh[v] = true
+			canonical := textproto.CanonicalMIMEHeaderKey(v)
+			sh[canonical] = true
 		}
 	}
 

lura/proxy_tracer.go

@@ -3,6 +3,7 @@ package lura
 import (
 	"context"
 	"errors"
+	"net/textproto"
 	"strings"
 
 	"go.opentelemetry.io/otel/attribute"
@@ -36,7 +37,8 @@ func newMiddlewareTracer(s state.OTEL, name string, stageName string, reportHead
 	if len(skipHeaders) > 0 {
 		sh = make(map[string]bool, len(skipHeaders))
 		for _, k := range skipHeaders {
-			sh[k] = true
+			canonical := textproto.CanonicalMIMEHeaderKey(k)
+			sh[canonical] = true
 		}
 	}
 	return &middlewareTracer{