Add interruptBegin and interruptEnd methods

This allows one to employ custom logging facilities during an interrupt,
like for example when one wants to log both to a file and to lines above
the bar.

Readme.md

@@ -139,6 +139,15 @@ var timer = setInterval(function () {
 }, 1000);
 ```
 
+It's also possible to start and stop interrupts manually, allowing synchronous
+logging between through the `interruptBegin` and `interruptEnd` methods:
+
+```js
+bar.interruptBegin();
+console.log('message');
+bar.interruptEnd();
+```
+
 You can see more examples in the `examples` folder.
 
 ## License

lib/node-progress.js

@@ -215,6 +215,27 @@ ProgressBar.prototype.interrupt = function (message) {
   this.stream.write(this.lastDraw);
 };
 
+/**
+ * Begin a interrupt so the user can manually write messages above the bar.
+ *
+ * @api public
+ */
+
+ProgressBar.prototype.interruptBegin = function () {
+  this.stream.clearLine();
+  this.stream.cursorTo(0);
+};
+
+/**
+ * End a interrupt, rendering the last draw again.
+ *
+ * @api public
+ */
+
+ProgressBar.prototype.interruptEnd = function () {
+  this.stream.write(this.lastDraw);
+};
+
 /**
  * Terminates a progress bar.
  *