Added an example for error related behaviors of ping-pong.

.gitignore

@@ -4,3 +4,6 @@ vendor/
 # Commit your application's lock file http://getcomposer.org/doc/01-basic-usage.md#composer-lock-the-lock-file
 # You may choose to ignore a library lock file http://getcomposer.org/doc/02-libraries.md#lock-file
 # composer.lock
+examples/ping-pong-with-error/err-pong.txt
+examples/ping-pong-with-error/exc-pong.txt
+examples/ping-pong-with-error/log-pong.txt

examples/ping-pong-with-error/ping.php

@@ -0,0 +1,77 @@
+<?php
+
+require dirname(dirname(__DIR__)) . '/vendor/autoload.php';
+
+use React\ChildProcess\Process;
+use React\EventLoop\Factory;
+use WyriHaximus\React\ChildProcess\Pool\Factory\Flexible;
+use WyriHaximus\React\ChildProcess\Pool\PoolInterface;
+
+const POOL_PROCESS_COUNT = 4;
+const I = 3;
+
+$loop = Factory::create();
+Flexible::create(
+    new Process('php '. dirname(dirname(__DIR__)) .'/examples/ping-pong-with-error/pong.php'),
+    $loop,
+    [ 'min_size' => 1, 'max_size' => POOL_PROCESS_COUNT ]
+)->then(function (PoolInterface $pool) use ($loop) {
+    $pool->on('message', function ($message) {
+        var_export($message);
+    });
+
+    $pool->on('error', function ($e) {
+        echo 'Error: ', var_export($e, true), PHP_EOL;
+    });
+
+    for ($i = 0; $i < I; $i++) {
+        echo "$i ";
+        $j = $i;
+        $pool->rpc(\WyriHaximus\React\ChildProcess\Messenger\Messages\Factory::rpc('ping', [
+            'i' => $i,
+        ]))->then(function ($data) use ($j) {
+            echo "Answer for $j * $j * $j * $j: ", $data['result'], PHP_EOL;
+        }, function ($error) {
+            var_export($error);
+            die();
+        });
+    }
+    echo PHP_EOL;
+
+    $timer = $loop->addPeriodicTimer(0.5, function () use ($pool) {
+        $status = 'Pool status: ';
+        foreach ($pool->info() as $key => $value) {
+            $status .= "    $key: $value";
+        }
+        echo $status, PHP_EOL;
+    });
+
+    $loop->addTimer(2, function () use ($pool, $timer, $loop) {
+        for ($i = 0; $i < I; $i++) {
+            echo "$i ";
+            $j = $i;
+            $pool->rpc(\WyriHaximus\React\ChildProcess\Messenger\Messages\Factory::rpc('ping', [
+                'i' => $i,
+            ]))->then(function ($data) use ($j) {
+                echo "Answer for $j * $j * $j * $j: ", $data['result'], PHP_EOL;
+            }, function ($error) {
+                var_export($error);
+                die();
+            });
+        }
+        echo PHP_EOL;
+
+        $pool->rpc(\WyriHaximus\React\ChildProcess\Messenger\Messages\Factory::rpc('ping', [
+            'i' => ++$i,
+        ]))->then(function () use ($pool, $timer, $loop) {
+            echo 'Terminating pool', PHP_EOL;
+            $pool->terminate(\WyriHaximus\React\ChildProcess\Messenger\Messages\Factory::message([
+                'woeufh209h838392',
+            ]));
+            $timer->cancel();
+            echo 'Done!!!', PHP_EOL;
+        });
+    });
+});
+
+$loop->run();

examples/ping-pong-with-error/pong.php

@@ -0,0 +1,54 @@
+<?php
+
+require dirname(dirname(__DIR__)) . '/vendor/autoload.php';
+
+use React\EventLoop\Factory;
+use WyriHaximus\React\ChildProcess\Messenger\Messages\Payload;
+use WyriHaximus\React\ChildProcess\Messenger\Messenger;
+
+error_reporting(-1);
+ini_set('display_errors', true);
+ini_set('error_log', 'err-pong.txt');
+
+$loop = Factory::create();
+$recipient = \WyriHaximus\React\ChildProcess\Messenger\Factory::child($loop);
+$recipient->on('message', function (Payload $payload, Messenger $messenger) use ($loop, $recipient) {
+    trigger_error('An error not interrupting unless caught.');
+    try {
+        file_put_contents(
+            'log-pong.txt',
+            'Got msg: '. var_export($payload->getPayload(), true) . PHP_EOL,
+            FILE_APPEND
+        );
+        $messenger->message(\WyriHaximus\React\ChildProcess\Messenger\Messages\Factory::message([
+            'No one seems receiving this.'
+        ]));
+        $recipient->message(\WyriHaximus\React\ChildProcess\Messenger\Messages\Factory::message([
+            'No one seems receiving this, either.'
+        ]));
+        $loop->stop();
+        throw new Exception('An exception to be caught.');
+    } catch (Exception $e) {
+        file_put_contents('exc-pong.txt', $e->getMessage() . PHP_EOL, FILE_APPEND);
+        $messenger->softTerminate();
+    }
+    throw new Exception('An exception to become an event.');
+});
+$recipient->on('error', function (Exception $e) {
+    file_put_contents('exc-pong.txt', $e->getMessage() . PHP_EOL, FILE_APPEND);
+});
+$recipient->registerRpc('ping', function (Payload $payload, Messenger $messenger) use ($loop) {
+    $stopAt = time() + mt_rand(1, 2);
+
+    do {
+        // Do nothing
+    } while ($stopAt >= time());
+
+//    trigger_error('An error to cause infinite loop if not caught.');
+
+    return \React\Promise\resolve([
+        'result' => $payload['i'] * $payload['i'] * $payload['i'] * $payload['i'],
+    ]);
+});
+
+$loop->run();