You can now take turns and control the VM.

src/Framebuffer.ts

@@ -0,0 +1,44 @@
+import { Mutex } from "async-mutex";
+
+export default class Framebuffer {
+    private fb : Buffer;
+    private writemutex : Mutex;
+    size : {height : number, width : number};
+    constructor() {
+        this.fb = Buffer.alloc(1);
+        this.size = {height: 0, width: 0};
+        this.writemutex = new Mutex();
+    }
+    setSize(w : number, h : number) {
+        var size = h * w * 4;
+        this.size.height = h;
+        this.size.width = w;
+        this.fb = Buffer.alloc(size);
+    }
+    loadDirtyRect(rect : Buffer, x : number, y : number, width : number, height : number) {
+        if (this.fb.length < rect.length)
+            throw new Error("Dirty rect larger than framebuffer (did you forget to set the size?)");
+        this.writemutex.runExclusive(() => {
+            return new Promise<void>((res, rej) => {
+                var byteswritten = 0;
+                for (var i = 0; i < height; i++) {
+                    byteswritten += rect.copy(this.fb, 4 * ((y + i) * this.size.width + x), byteswritten, byteswritten + (width * 4));
+                }
+                res();
+            })
+        });
+    }
+    getFb() : Promise<Buffer> {
+        return new Promise<Buffer>(async (res, rej) => {
+            var v = await this.writemutex.runExclusive(() => {
+                return new Promise<Buffer>((reso, reje) => {
+                    var buff = Buffer.alloc(this.fb.length);
+                    this.fb.copy(buff);
+                    reso(buff);
+                });
+            });
+            res(v);
+        })
+    }
+
+}