Explicitly specifying the type of input and output parameters to chunk method

This is just a proposal - The chunk step builder currently depends on the input and output type as generic parameters:

    stepBuilderFactory.get("step1").<Person, Person>chunk(10)

Instead, I think it is better from a users perspective to be explicit and have an overloaded version of chunk which accepts two more Class parameters and infers the type from that:
    
    stepBuilderFactory.get("step1").chunk(10, Person.class, Person.class)