From cd8ad435d62a355b3fd729d21f80fd4e8396bbcc Mon Sep 17 00:00:00 2001
From: Alan Zimmer <48699787+alzimmermsft@users.noreply.github.com>
Date: Tue, 28 Sep 2021 15:30:09 -0700
Subject: [PATCH] Hide HttpHeaders.toMultiMap API (#24428)

---
 .../NettyToAzureCoreHttpHeadersWrapper.java            |  3 +--
 .../src/main/java/com/azure/core/http/HttpHeaders.java |  2 +-
 .../main/java/com/azure/core/http/rest/RestProxy.java  | 10 ++++++++--
 3 files changed, 10 insertions(+), 5 deletions(-)

diff --git a/sdk/core/azure-core-http-netty/src/main/java/com/azure/core/http/netty/implementation/NettyToAzureCoreHttpHeadersWrapper.java b/sdk/core/azure-core-http-netty/src/main/java/com/azure/core/http/netty/implementation/NettyToAzureCoreHttpHeadersWrapper.java
index 788d2671cdfba..b1beed6ed4502 100644
--- a/sdk/core/azure-core-http-netty/src/main/java/com/azure/core/http/netty/implementation/NettyToAzureCoreHttpHeadersWrapper.java
+++ b/sdk/core/azure-core-http-netty/src/main/java/com/azure/core/http/netty/implementation/NettyToAzureCoreHttpHeadersWrapper.java
@@ -130,8 +130,7 @@ public Map<String, String> toMap() {
         return abstractMap;
     }
 
-    @Override
-    public Map<String, String[]> toMultiMap() {
+    Map<String, String[]> toMultiMap() {
         if (abstractMultiMap == null) {
             abstractMultiMap = new DeferredCacheImmutableMap<>(LOGGER, new HashMap<>(), nettyHeaders,
                 getAll -> getAll.toArray(new String[0]));
diff --git a/sdk/core/azure-core/src/main/java/com/azure/core/http/HttpHeaders.java b/sdk/core/azure-core/src/main/java/com/azure/core/http/HttpHeaders.java
index 664f7fa4d5e46..c9f1e0d9fb0e6 100644
--- a/sdk/core/azure-core/src/main/java/com/azure/core/http/HttpHeaders.java
+++ b/sdk/core/azure-core/src/main/java/com/azure/core/http/HttpHeaders.java
@@ -250,7 +250,7 @@ public Map<String, String> toMap() {
      *
      * @return the headers in a copied and unmodifiable form.
      */
-    public Map<String, String[]> toMultiMap() {
+    Map<String, String[]> toMultiMap() {
         final Map<String, String[]> result = new HashMap<>();
         for (final HttpHeader header : headers.values()) {
             result.put(header.getName(), header.getValues());
diff --git a/sdk/core/azure-core/src/main/java/com/azure/core/http/rest/RestProxy.java b/sdk/core/azure-core/src/main/java/com/azure/core/http/rest/RestProxy.java
index 9f84a39354407..3fe5d9cfba7c1 100644
--- a/sdk/core/azure-core/src/main/java/com/azure/core/http/rest/RestProxy.java
+++ b/sdk/core/azure-core/src/main/java/com/azure/core/http/rest/RestProxy.java
@@ -201,10 +201,16 @@ static Flux<ByteBuffer> validateLength(final HttpRequest request) {
      * @return The updated context containing the span context.
      */
     private Context startTracingSpan(Method method, Context context) {
-        boolean disableTracing = (boolean) context.getData(Tracer.DISABLE_TRACING_KEY).orElse(false);
-        if (!TracerProxy.isTracingEnabled() || disableTracing) {
+        // First check if tracing is enabled. This is an optimized operation, so it is done first.
+        if (!TracerProxy.isTracingEnabled()) {
             return context;
         }
+
+        // Then check if this method disabled tracing. This requires walking a linked list, so do it last.
+        if ((boolean) context.getData(Tracer.DISABLE_TRACING_KEY).orElse(false)) {
+            return context;
+        }
+
         String spanName = interfaceParser.getServiceName() + "." + method.getName();
         context = TracerProxy.setSpanName(spanName, context);
         return TracerProxy.start(spanName, context);