Run test on node 20

.appveyor.yml

@@ -2,6 +2,7 @@ build: off
 
 environment:
   matrix:
+    - nodejs_version: '20'
     - nodejs_version: '18'
     - nodejs_version: '16'
     - nodejs_version: '14'

.github/workflows/nodejs.yml

@@ -13,7 +13,7 @@ jobs:
 
     strategy:
       matrix:
-        node-version: ["14.x", "16.x", "18.x"]
+        node-version: ["14.x", "16.x", "18.x", "20.x"]
 
     steps:
     - uses: actions/checkout@v2
@@ -29,7 +29,7 @@ jobs:
 
     strategy:
       matrix:
-        node-version: ["14.x", "16.x", "18.x"]
+        node-version: ["14.x", "16.x", "18.x", "20.x"]
 
     steps:
     - uses: actions/checkout@v2

lib/loaders/load.mjs

@@ -32,6 +32,6 @@ export const globalPreload = (context) => {
   return `
 port.on('message', (m) => {
   if (process.connected) process.send(m);
-});
+}).unref();
   `;
 };