def merge source
      result = nil
      mutex.synchronize do
        result = workspace.merge(source)
        @synchronized = !result if synchronized?
      end
      result
    end
def merge source
      result = nil
      mutex.synchronize do
        result = workspace.merge(source)
        @synchronized = !result if synchronized?
      end
      result
    end
Try to merge a source into the library's workspace. If the workspace is
 not configured to include the source, it gets ignored.

 @param source [Source]
 @return [Boolean] True if the source was merged into the workspace.