Merge branch 'master' into 3.0-merge

# Conflicts:
#	composer.json
#	src/testing/co-phpunit

Author: limingxinleo

src/ScanHandler/PcntlScanHandler.php

@@ -15,6 +15,20 @@
 
 class PcntlScanHandler implements ScanHandlerInterface
 {
+    public function __construct()
+    {
+        if (! extension_loaded('pcntl')) {
+            throw new Exception('Missing pcntl extension.');
+        }
+        if (extension_loaded('grpc')) {
+            $grpcForkSupport = ini_get_all('grpc')['grpc.enable_fork_support']['local_value'];
+            $grpcForkSupport = strtolower(trim(str_replace('0', '', $grpcForkSupport)));
+            if (in_array($grpcForkSupport, ['', 'off', 'false'], true)) {
+                throw new Exception(' Grpc fork support must be enabled before the server starts, please set grpc.enable_fork_support = 1 in your php.ini.');
+            }
+        }
+    }
+
     public function scan(): Scanned
     {
         $pid = pcntl_fork();