This just cleans up the code, probably no fix (#2066)

* clean up todo_writing

outbound/hmail.js

@@ -113,7 +113,7 @@ HMailItem.prototype.read_todo = function () {
         // I'm making the assumption here we won't ever read less than 4 bytes
         // as no filesystem on the planet should be that dumb...
         tl_reader.destroy();
-        const todo_len = (buf[0] << 24) + (buf[1] << 16) + (buf[2] << 8) + buf[3];
+        const todo_len = buf.readUInt32BE(0);
         const td_reader = fs.createReadStream(self.path, {encoding: 'utf8', start: 4, end: todo_len + 3});
         self.data_start = todo_len + 4;
         let todo = '';

outbound/index.js

@@ -319,20 +319,15 @@ exports.build_todo = function (todo, ws, write_more) {
                 return value;
         }
     }
-    const todo_str = new Buffer(JSON.stringify(todo, exclude_from_json));
 
-    // since JS has no pack() we have to manually write the bytes of a long
-    const todo_length = new Buffer(4);
-    const todo_l = todo_str.length;
-    todo_length[3] =  todo_l        & 0xff;
-    todo_length[2] = (todo_l >>  8) & 0xff;
-    todo_length[1] = (todo_l >> 16) & 0xff;
-    todo_length[0] = (todo_l >> 24) & 0xff;
-
-    const buf = Buffer.concat([todo_length, todo_str], todo_str.length + 4);
+    const todo_json = JSON.stringify(todo, exclude_from_json);
+    const buf = new Buffer(4 + todo_json.length);
+    buf.writeUInt32BE(todo_json.length, 0);
+    buf.write(todo_json, 4);
 
     const continue_writing = ws.write(buf);
-    if (continue_writing) return write_more();
+    if (continue_writing) return process.nextTick(write_more);
+
     ws.once('drain', write_more);
 };