def save!(&block)
      # TODO: this shouldn't need to be run, but if no attributes are assigned, then
      # if needs to be run.  Maybe there's a better way to handle it.
      validate!.then do
        # Get errors from validate
        errors = self.errors.to_h

        result = nil

        if errors.size == 0
          # cache save_to in a local
          save_to = self.save_to
          if save_to
            if save_to.is_a?(ArrayModel)
              # Add to the collection
              promise = save_to.create(attributes)
            else
              # We have a saved model
              promise = save_to.assign_attributes(attributes)
            end

            result = promise.then do |new_model|
              # The main model saved, so mark the buffer as not new
              @new = false

              if new_model
                # Mark the model as loaded
                new_model.change_state_to(:loaded_state, :loaded)

                # Set the buffer's id to track the main model's id
                self.save_to = new_model
              end

              # Copy attributes back from save_to model
              @attributes = new_model.attributes

              # Remove tracked changes
              clear_tracked_changes!

              new_model
            end.fail do |errors|
              if errors.is_a?(Hash)
                server_errors.replace(errors)

                # Merge the server errors into the main errors
                self.errors.merge!(server_errors.to_h)
              end

              promise_for_errors(errors)
            end
          else
            fail 'Model is not a buffer, can not be saved, modifications should be persisted as they are made.'
          end
        else
          # Some errors, mark all fields
          result = promise_for_errors(errors)
        end

        # If passed a block, call then on it with the block.
        result = result.then(&block) if block

        result
      end
    end
def save!(&block)
      # TODO: this shouldn't need to be run, but if no attributes are assigned, then
      # if needs to be run.  Maybe there's a better way to handle it.
      validate!.then do
        # Get errors from validate
        errors = self.errors.to_h

        result = nil

        if errors.size == 0
          # cache save_to in a local
          save_to = self.save_to
          if save_to
            if save_to.is_a?(ArrayModel)
              # Add to the collection
              promise = save_to.create(attributes)
            else
              # We have a saved model
              promise = save_to.assign_attributes(attributes)
            end

            result = promise.then do |new_model|
              # The main model saved, so mark the buffer as not new
              @new = false

              if new_model
                # Mark the model as loaded
                new_model.change_state_to(:loaded_state, :loaded)

                # Set the buffer's id to track the main model's id
                self.save_to = new_model
              end

              # Copy attributes back from save_to model
              @attributes = new_model.attributes

              # Remove tracked changes
              clear_tracked_changes!

              new_model
            end.fail do |errors|
              if errors.is_a?(Hash)
                server_errors.replace(errors)

                # Merge the server errors into the main errors
                self.errors.merge!(server_errors.to_h)
              end

              promise_for_errors(errors)
            end
          else
            fail 'Model is not a buffer, can not be saved, modifications should be persisted as they are made.'
          end
        else
          # Some errors, mark all fields
          result = promise_for_errors(errors)
        end

        # If passed a block, call then on it with the block.
        result = result.then(&block) if block

        result
      end
    end
Save saves the contents of a buffer to the save_to location.  If the buffer is new, it will create a new
 model to save to.  Otherwise it will be an existing model.  Save returns a promise that may fail with
 validation errors from the server (or the client).  You can also pass a block as a shortcut to calling
 ```.save!.then do```