diff --git a/adb/adb.cpp b/adb/adb.cpp
index 0518e9d..08d3904 100644
--- a/adb/adb.cpp
+++ b/adb/adb.cpp
@@ -1198,9 +1198,9 @@
         FeatureSet features = supported_features();
         // Abuse features to report libusb status.
         if (should_use_libusb()) {
-            features.insert(kFeatureLibusb);
+            features.emplace_back(kFeatureLibusb);
         }
-        features.insert(kFeaturePushSync);
+        features.emplace_back(kFeaturePushSync);
         SendOkay(reply_fd, FeatureSetToString(features));
         return HostRequestResult::Handled;
     }
diff --git a/adb/client/adb_client.cpp b/adb/client/adb_client.cpp
index c859d75..0ad0465 100644
--- a/adb/client/adb_client.cpp
+++ b/adb/client/adb_client.cpp
@@ -37,6 +37,7 @@
 #include <vector>
 
 #include <android-base/file.h>
+#include <android-base/no_destructor.h>
 #include <android-base/stringprintf.h>
 #include <android-base/strings.h>
 #include <android-base/thread_annotations.h>
@@ -415,18 +416,14 @@
     return android::base::StringPrintf("%s:%s", prefix, command);
 }
 
-bool adb_get_feature_set(FeatureSet* feature_set, std::string* error) {
-    static FeatureSet* features = nullptr;
-    if (!features) {
+const FeatureSet& adb_get_feature_set() {
+    static const android::base::NoDestructor<FeatureSet> features([] {
         std::string result;
-        if (adb_query(format_host_command("features"), &result, error)) {
-            features = new FeatureSet(StringToFeatureSet(result));
+        if (!adb_query(format_host_command("features"), &result, &result)) {
+            fprintf(stderr, "failed to get feature set: %s\n", result.c_str());
+            return FeatureSet{};
         }
-    }
-    if (features) {
-        *feature_set = *features;
-        return true;
-    }
-    feature_set->clear();
-    return false;
+        return StringToFeatureSet(result);
+    }());
+    return *features;
 }
diff --git a/adb/client/adb_client.h b/adb/client/adb_client.h
index 1c6cde7..bf0be40 100644
--- a/adb/client/adb_client.h
+++ b/adb/client/adb_client.h
@@ -76,7 +76,7 @@
 std::string format_host_command(const char* _Nonnull command);
 
 // Get the feature set of the current preferred transport.
-bool adb_get_feature_set(FeatureSet* _Nonnull feature_set, std::string* _Nonnull error);
+const FeatureSet& adb_get_feature_set();
 
 #if defined(__linux__)
 // Get the path of a file containing the path to the server executable, if the socket spec set via
diff --git a/adb/client/adb_install.cpp b/adb/client/adb_install.cpp
index da3154e..3810cc8 100644
--- a/adb/client/adb_install.cpp
+++ b/adb/client/adb_install.cpp
@@ -57,10 +57,8 @@
 }
 
 static bool can_use_feature(const char* feature) {
-    FeatureSet features;
-    std::string error;
-    if (!adb_get_feature_set(&features, &error)) {
-        fprintf(stderr, "error: %s\n", error.c_str());
+    auto&& features = adb_get_feature_set();
+    if (features.empty()) {
         return false;
     }
     return CanUseFeature(features, feature);
diff --git a/adb/client/commandline.cpp b/adb/client/commandline.cpp
index ceb21d5..6a7493f 100644
--- a/adb/client/commandline.cpp
+++ b/adb/client/commandline.cpp
@@ -672,10 +672,8 @@
 }
 
 static int adb_shell(int argc, const char** argv) {
-    FeatureSet features;
-    std::string error_message;
-    if (!adb_get_feature_set(&features, &error_message)) {
-        fprintf(stderr, "error: %s\n", error_message.c_str());
+    auto&& features = adb_get_feature_set();
+    if (features.empty()) {
         return 1;
     }
 
@@ -779,13 +777,10 @@
 }
 
 static int adb_abb(int argc, const char** argv) {
-    FeatureSet features;
-    std::string error_message;
-    if (!adb_get_feature_set(&features, &error_message)) {
-        fprintf(stderr, "error: %s\n", error_message.c_str());
+    auto&& features = adb_get_feature_set();
+    if (features.empty()) {
         return 1;
     }
-
     if (!CanUseFeature(features, kFeatureAbb)) {
         error_exit("abb is not supported by the device");
     }
@@ -1164,9 +1159,8 @@
         // Use shell protocol if it's supported and the caller doesn't explicitly
         // disable it.
         if (!disable_shell_protocol) {
-            FeatureSet features;
-            std::string error;
-            if (adb_get_feature_set(&features, &error)) {
+            auto&& features = adb_get_feature_set();
+            if (!features.empty()) {
                 use_shell_protocol = CanUseFeature(features, kFeatureShell2);
             } else {
                 // Device was unreachable.
@@ -1816,10 +1810,8 @@
         }
         return adb_connect_command(android::base::StringPrintf("tcpip:%d", port));
     } else if (!strcmp(argv[0], "remount")) {
-        FeatureSet features;
-        std::string error;
-        if (!adb_get_feature_set(&features, &error)) {
-            fprintf(stderr, "error: %s\n", error.c_str());
+        auto&& features = adb_get_feature_set();
+        if (features.empty()) {
             return 1;
         }
 
@@ -2042,10 +2034,8 @@
     } else if (!strcmp(argv[0], "track-jdwp")) {
         return adb_connect_command("track-jdwp");
     } else if (!strcmp(argv[0], "track-app")) {
-        FeatureSet features;
-        std::string error;
-        if (!adb_get_feature_set(&features, &error)) {
-            fprintf(stderr, "error: %s\n", error.c_str());
+        auto&& features = adb_get_feature_set();
+        if (features.empty()) {
             return 1;
         }
         if (!CanUseFeature(features, kFeatureTrackApp)) {
@@ -2074,10 +2064,8 @@
         return 0;
     } else if (!strcmp(argv[0], "features")) {
         // Only list the features common to both the adb client and the device.
-        FeatureSet features;
-        std::string error;
-        if (!adb_get_feature_set(&features, &error)) {
-            fprintf(stderr, "error: %s\n", error.c_str());
+        auto&& features = adb_get_feature_set();
+        if (features.empty()) {
             return 1;
         }
 
diff --git a/adb/client/file_sync_client.cpp b/adb/client/file_sync_client.cpp
index 6816734..f2c673a 100644
--- a/adb/client/file_sync_client.cpp
+++ b/adb/client/file_sync_client.cpp
@@ -225,13 +225,14 @@
 
 class SyncConnection {
   public:
-    SyncConnection() : acknowledgement_buffer_(sizeof(sync_status) + SYNC_DATA_MAX) {
+    SyncConnection()
+        : acknowledgement_buffer_(sizeof(sync_status) + SYNC_DATA_MAX),
+          features_(adb_get_feature_set()) {
         acknowledgement_buffer_.resize(0);
         max = SYNC_DATA_MAX; // TODO: decide at runtime.
 
-        std::string error;
-        if (!adb_get_feature_set(&features_, &error)) {
-            Error("failed to get feature set: %s", error.c_str());
+        if (features_.empty()) {
+            Error("failed to get feature set");
         } else {
             have_stat_v2_ = CanUseFeature(features_, kFeatureStat2);
             have_ls_v2_ = CanUseFeature(features_, kFeatureLs2);
@@ -239,6 +240,7 @@
             have_sendrecv_v2_brotli_ = CanUseFeature(features_, kFeatureSendRecv2Brotli);
             have_sendrecv_v2_lz4_ = CanUseFeature(features_, kFeatureSendRecv2LZ4);
             have_sendrecv_v2_dry_run_send_ = CanUseFeature(features_, kFeatureSendRecv2DryRunSend);
+            std::string error;
             fd.reset(adb_connect("sync:", &error));
             if (fd < 0) {
                 Error("connect failed: %s", error.c_str());
@@ -919,7 +921,7 @@
   private:
     std::deque<std::pair<std::string, std::string>> deferred_acknowledgements_;
     Block acknowledgement_buffer_;
-    FeatureSet features_;
+    const FeatureSet& features_;
     bool have_stat_v2_;
     bool have_ls_v2_;
     bool have_sendrecv_v2_;
diff --git a/adb/transport.cpp b/adb/transport.cpp
index cc2e0e3..963c3c1 100644
--- a/adb/transport.cpp
+++ b/adb/transport.cpp
@@ -29,7 +29,6 @@
 #include <unistd.h>
 
 #include <algorithm>
-#include <deque>
 #include <list>
 #include <memory>
 #include <mutex>
@@ -40,6 +39,7 @@
 #include <adb/crypto/x509_generator.h>
 #include <adb/tls/tls_connection.h>
 #include <android-base/logging.h>
+#include <android-base/no_destructor.h>
 #include <android-base/parsenetaddress.h>
 #include <android-base/stringprintf.h>
 #include <android-base/strings.h>
@@ -1170,28 +1170,29 @@
 }
 
 const FeatureSet& supported_features() {
-    // Local static allocation to avoid global non-POD variables.
-    static const FeatureSet* features = new FeatureSet{
-            kFeatureShell2,
-            kFeatureCmd,
-            kFeatureStat2,
-            kFeatureLs2,
-            kFeatureFixedPushMkdir,
-            kFeatureApex,
-            kFeatureAbb,
-            kFeatureFixedPushSymlinkTimestamp,
-            kFeatureAbbExec,
-            kFeatureRemountShell,
-            kFeatureTrackApp,
-            kFeatureSendRecv2,
-            kFeatureSendRecv2Brotli,
-            kFeatureSendRecv2LZ4,
-            kFeatureSendRecv2DryRunSend,
-            // Increment ADB_SERVER_VERSION when adding a feature that adbd needs
-            // to know about. Otherwise, the client can be stuck running an old
-            // version of the server even after upgrading their copy of adb.
-            // (http://b/24370690)
-    };
+    static const android::base::NoDestructor<FeatureSet> features([] {
+        return FeatureSet{
+                kFeatureShell2,
+                kFeatureCmd,
+                kFeatureStat2,
+                kFeatureLs2,
+                kFeatureFixedPushMkdir,
+                kFeatureApex,
+                kFeatureAbb,
+                kFeatureFixedPushSymlinkTimestamp,
+                kFeatureAbbExec,
+                kFeatureRemountShell,
+                kFeatureTrackApp,
+                kFeatureSendRecv2,
+                kFeatureSendRecv2Brotli,
+                kFeatureSendRecv2LZ4,
+                kFeatureSendRecv2DryRunSend,
+                // Increment ADB_SERVER_VERSION when adding a feature that adbd needs
+                // to know about. Otherwise, the client can be stuck running an old
+                // version of the server even after upgrading their copy of adb.
+                // (http://b/24370690)
+        };
+    }());
 
     return *features;
 }
@@ -1205,16 +1206,20 @@
         return FeatureSet();
     }
 
-    auto names = android::base::Split(features_string, ",");
-    return FeatureSet(names.begin(), names.end());
+    return android::base::Split(features_string, ",");
+}
+
+template <class Range, class Value>
+static bool contains(const Range& r, const Value& v) {
+    return std::find(std::begin(r), std::end(r), v) != std::end(r);
 }
 
 bool CanUseFeature(const FeatureSet& feature_set, const std::string& feature) {
-    return feature_set.count(feature) > 0 && supported_features().count(feature) > 0;
+    return contains(feature_set, feature) && contains(supported_features(), feature);
 }
 
 bool atransport::has_feature(const std::string& feature) const {
-    return features_.count(feature) > 0;
+    return contains(features_, feature);
 }
 
 void atransport::SetFeatures(const std::string& features_string) {
diff --git a/adb/transport.h b/adb/transport.h
index 4b2e000..e93c31c 100644
--- a/adb/transport.h
+++ b/adb/transport.h
@@ -30,7 +30,7 @@
 #include <string>
 #include <string_view>
 #include <thread>
-#include <unordered_set>
+#include <vector>
 
 #include <android-base/macros.h>
 #include <android-base/thread_annotations.h>
@@ -40,7 +40,10 @@
 #include "adb_unique_fd.h"
 #include "types.h"
 
-typedef std::unordered_set<std::string> FeatureSet;
+// Even though the feature set is used as a set, we only have a dozen or two
+// of available features at any moment. Vector works much better in terms of
+// both memory usage and performance for these sizes.
+using FeatureSet = std::vector<std::string>;
 
 namespace adb {
 namespace tls {
diff --git a/adb/transport_test.cpp b/adb/transport_test.cpp
index 00beb3a..a9ada4a 100644
--- a/adb/transport_test.cpp
+++ b/adb/transport_test.cpp
@@ -66,7 +66,7 @@
     ASSERT_TRUE(t.has_feature("bar"));
 
     t.SetFeatures(FeatureSetToString(FeatureSet{"foo", "bar", "foo"}));
-    ASSERT_EQ(2U, t.features().size());
+    ASSERT_LE(2U, t.features().size());
     ASSERT_TRUE(t.has_feature("foo"));
     ASSERT_TRUE(t.has_feature("bar"));