error plugin can now into headers

plugins/error/index.js

@@ -23,6 +23,8 @@
             type: "http",
             // only valid if type: http
             code: 500,
+            // valid only if type: http
+            headers: {},
             // valid either way
             message: "Internal server error"
         }
@@ -43,14 +45,17 @@
             LR.log(pluginName, `erroring out for: ${url} — HTTP error`)
             
             // I guess we want a HTTP error then
-            
             var responseInit = {
                 status:     config.code,
                 statusText: config.message,
-                headers: {},
+                headers: config.headers,
                 url: url
             };
-            responseInit.headers['Content-Type'] = "text/plain"
+            
+            // we need some content type here
+            if (responseInit.headers['Content-Type'] === undefined) {
+                responseInit.headers['Content-Type'] = "text/plain"
+            }
             
             let blob = new Blob(
                             [config.message],