class_docstr: Reader that reads from an upstream reader, calls the processor, and returns
  the processed record.
class_docstr_tok: ["Reader","that","reads","from","an","upstream","reader",",","calls","the","processor",",","and","returns","the","processed","record","."]
code: def schema(self):
      return self.processor.schema()
  
imports: from caffe2.python import core, queue_util
  from caffe2.python.dataio import Reader, Writer
  from caffe2.python.net_builder import NetBuilder, ops
  from caffe2.python.schema import as_record, Field
  from caffe2.python.task import Node, Task, TaskGroup
label_desc: Use image node_id 2 for calling the ProcessingReader obj's underlying member method code with example usage: obj.schema() and returns: self