Method category index
creating instances (class)
still unclassified (instance)
Invoke aBlock at an indeterminate time in an indeterminate process before answering its value from #value sent to my result.
This method should not be called for instances of this class.
Answer whether calling #value will raise an exception.
Answer whether we already have a value (or calling #value will raise an error).
Get the value of the receiver.
Set the value of the receiver.
Private - set the initial state of the receiver
Print a representation of the receiver
Private - Raise anException whenever #value is called.