Details
Description
If a PushbackInputStream is passed to XmlHeaderAwareReader, the class attempts to reuse that instance as a pushback inputstream without knowing any details about the existing pushback buffer.
If I pass a PushbackInputStream with a buffer size of 1 into XmlHeaderAwareReader, it will attempt to unread more than 1 byte and cause an IOException("Pushback buffer is full")
Patch and test case