code: @Nullable
  	@Override
  	public String getMapping(Class<?> type, Method method) {
  
  		String key = key(type, method);
  
  		return MAPPINGS.computeIfAbsent(key, __ -> delegate.getMapping(type, method));
  	}
docs: /*
  (non-Javadoc)
  @see org.springframework.hateoas.core.MappingDiscoverer#getMapping(java.lang.Class, java.lang.reflect.Method)