what is _hasConnectPatch in http.ServerResponse.prototype

I am looking the patch.js in connect module. There are some code as follows:

var http = require('http') , res = http.ServerResponse.prototype;

...

if (!res._hasConnectPatch) { ....

here what is the _hasConnectPatch property ? it is not in the description of the API doc in the node.js org. where can I find the description of _hasConnectPatch ?

it's a boolean flag that avoids applying the code in patch.js twice. patch.js provides "header sent" flag.

If you look at the comment just before the if in the code you'll see // apply only once and near the end of the file :

res._hasConnectPatch = true

It's not in node docs because it's a connect extension.