class_docstr: This class handles iteration events to print output to the console.
code: def __init__(self, **_unused):
      ITER_STARTED.connect(self.read_console_vars)
      ITER_FINISHED.connect(self.print_console_vars)
  
imports: import tensorflow
  from niftynet.engine.application_variables import CONSOLE
  from niftynet.engine.signal import ITER_STARTED, ITER_FINISHED
label_desc: Use image node_id 1 to create a new ConsoleLogger object from inherited base classes: object with example: obj = ConsoleLogger()