Add warning in examples if xdebug or assertions are enabled

examples/delayed-response.php

@@ -1,14 +1,15 @@
 #!/usr/bin/env php
 <?php
 
-require dirname(__DIR__) . "/vendor/autoload.php";
+require __DIR__ . "/support/bootstrap.php";
 
 use Amp\ByteStream\ResourceOutputStream;
 use Amp\Delayed;
 use Amp\Http\Server\Request;
 use Amp\Http\Server\RequestHandler\CallableRequestHandler;
 use Amp\Http\Server\Response;
 use Amp\Http\Server\Server;
+use Amp\Http\Server\Support\Recommender;
 use Amp\Http\Status;
 use Amp\Log\ConsoleFormatter;
 use Amp\Log\StreamHandler;
@@ -38,6 +39,8 @@
         ], "Hello, World!");
     }), $logger);
 
+    $server->attach(new Recommender);
+
     yield $server->start();
 
     // Stop the server when SIGINT is received (this is technically optional, but it is best to call Server::stop()).

examples/exception.php

@@ -1,9 +1,10 @@
 #!/usr/bin/env php
 <?php
 
-require dirname(__DIR__) . "/vendor/autoload.php";
+require __DIR__ . "/support/bootstrap.php";
 
 use Amp\ByteStream\ResourceOutputStream;
+use Amp\Http\Server\Support\Recommender;
 use Amp\Log\ConsoleFormatter;
 use Amp\Log\StreamHandler;
 use Amp\Http\Server\RequestHandler\CallableRequestHandler;
@@ -28,6 +29,8 @@
         throw new \Exception("Something went wrong :-(");
     }), $logger);
 
+    $server->attach(new Recommender);
+
     yield $server->start();
 
     // Stop the server when SIGINT is received (this is technically optional, but it is best to call Server::stop()).

examples/hello-world.php

@@ -1,13 +1,14 @@
 #!/usr/bin/env php
 <?php
 
-require dirname(__DIR__) . "/vendor/autoload.php";
+require __DIR__ . "/support/bootstrap.php";
 
 use Amp\ByteStream\ResourceOutputStream;
 use Amp\Http\Server\Request;
 use Amp\Http\Server\RequestHandler\CallableRequestHandler;
 use Amp\Http\Server\Response;
 use Amp\Http\Server\Server;
+use Amp\Http\Server\Support\Recommender;
 use Amp\Http\Status;
 use Amp\Log\ConsoleFormatter;
 use Amp\Log\StreamHandler;
@@ -33,6 +34,8 @@
         ], "Hello, World!");
     }), $logger);
 
+    $server->attach(new Recommender);
+
     yield $server->start();
 
     // Stop the server when SIGINT is received (this is technically optional, but it is best to call Server::stop()).

examples/state.php

@@ -1,13 +1,14 @@
 #!/usr/bin/env php
 <?php
 
-require dirname(__DIR__) . "/vendor/autoload.php";
+require __DIR__ . "/support/bootstrap.php";
 
 use Amp\ByteStream\ResourceOutputStream;
 use Amp\Http\Server\Request;
 use Amp\Http\Server\RequestHandler\CallableRequestHandler;
 use Amp\Http\Server\Response;
 use Amp\Http\Server\Server;
+use Amp\Http\Server\Support\Recommender;
 use Amp\Http\Status;
 use Amp\Log\ConsoleFormatter;
 use Amp\Log\StreamHandler;
@@ -39,6 +40,8 @@
         ], "You're visitor #" . (++$counter) . ".");
     }), $logger);
 
+    $server->attach(new Recommender);
+
     yield $server->start();
 
     // Stop the server when SIGINT is received (this is technically optional, but it is best to call Server::stop()).

examples/stream.php

@@ -1,7 +1,7 @@
 #!/usr/bin/env php
 <?php
 
-require dirname(__DIR__) . "/vendor/autoload.php";
+require __DIR__ . "/support/bootstrap.php";
 
 use Amp\ByteStream\IteratorStream;
 use Amp\ByteStream\ResourceOutputStream;
@@ -11,6 +11,7 @@
 use Amp\Http\Server\RequestHandler\CallableRequestHandler;
 use Amp\Http\Server\Response;
 use Amp\Http\Server\Server;
+use Amp\Http\Server\Support\Recommender;
 use Amp\Http\Status;
 use Amp\Log\ConsoleFormatter;
 use Amp\Log\StreamHandler;
@@ -43,6 +44,8 @@
         })));
     }), $logger, (new Options)->withoutCompression());
 
+    $server->attach(new Recommender);
+
     yield $server->start();
 
     // Stop the server when SIGINT is received (this is technically optional, but it is best to call Server::stop()).

examples/support/Recommender.php

@@ -0,0 +1,33 @@
+<?php
+
+namespace Amp\Http\Server\Support;
+
+use Amp\Http\Server\Server;
+use Amp\Http\Server\ServerObserver;
+use Amp\Promise;
+use Amp\Success;
+
+final class Recommender implements ServerObserver {
+    /** @inheritdoc */
+    public function onStart(Server $server): Promise {
+        $logger = $server->getLogger();
+
+        if (\extension_loaded('xdebug')) {
+            $logger->warning('The "xdebug" extension is loaded, this has a major impact on performance.');
+        }
+        try {
+            if (!@\assert(false)) {
+                $logger->warning("Assertions are enabled, this has a major impact on performance.");
+            }
+        } catch (\AssertionError $exception) {
+            $logger->warning("Assertions are enabled, this has a major impact on performance.");
+        }
+
+        return new Success;
+    }
+
+    /** @inheritdoc */
+    public function onStop(Server $server): Promise {
+        return new Success;
+    }
+}

examples/support/bootstrap.php

@@ -0,0 +1,5 @@
+<?php
+
+/** @var Composer\Autoload\ClassLoader $loader */
+$loader = require dirname(__DIR__, 2) . '/vendor/autoload.php';
+$loader->addPsr4('Amp\Http\Server\Support\\', __DIR__);