better representation of a function in error cause

Author: ZsharE

dist/elmahio.js

@@ -1030,7 +1030,7 @@
                         obj.ExceptionSpecific = [{ key: "cause", value: error.cause }];
                     }
                     if (typeof error.cause === "function") {
-                        obj.ExceptionSpecific = [{ key: "cause", value: error.cause.toString() }];
+                        obj.ExceptionSpecific = [{ key: "cause", value: Object.prototype.toString.call(error.cause) }];
                     }
                     if (typeof error.cause === "object") {
                         if (!(Object.keys(obj).length === 0 && obj.constructor === Object)) {