The AccumuloInputFormat required that the same exact Configuration object which was provided to its static configuration methods is also provided to its getSplits() and createRecordReader() methods.
In practice, some tools, like MultipleInputs or Pig, don't guarantee that the same Configuration object is provided to getSplits() and createRecordReader(). This tends to be a common method of interaction to ensure that multiple InputFormats don't collide with one another in the same Configuration object (e.g. FileInputFormat). By serialization the necessary information from the Configuration regarding how to query Accumulo into the InputSplit AccumuloInputFormat creates, we can alleviate this requirement and make client interaction a little more standard.