code: protected final void prepareInlineRemove(FluentModelTImpl model) {
          FluentModelTImpl childResource = find(model.childResourceKey());
          if (childResource != null) {
              throw new IllegalArgumentException(pendingOperationMessage(model.name(), model.childResourceKey()));
          }
          model.setPendingOperation(ExternalChildResourceImpl.PendingOperation.ToBeRemoved);
          this.childCollection.put(model.childResourceKey(), model);
          super.prepareForFutureCommitOrPostRun(model);
      }
docs: Prepare the given model of an external child resource for inline removal (along with the definition or update of parent resource).
  
  @param model the model representing child resource to remove