Descriptor
@Immutable
interface Descriptor
EnumDescriptor | 
                
                   Descriptor representing an enumeration, with its name and a map of its numeric values to value labels.  | 
              
NoOpDescriptor | 
                
                   Default (empty) implementation of   | 
              
StructDescriptor | 
                
                   Interface implemented by logical struct types.  | 
              
A tagging interface to describe a field, such as StructDescriptor