function arrayBufferToBinaryString(buffer) {
        var binary = '';
        var bytes = new Uint8Array(buffer);
        var length = bytes.byteLength;
        var i = -1;
        while (++i < length) {
            binary += String.fromCharCode(bytes[i]);
        }
        return binary;
    }
Convert an <code>ArrayBuffer</code> to a binary string.

Example:

```js
var myString = blobUtil.arrayBufferToBinaryString(arrayBuff)
```

@param buffer - array buffer
@returns binary string