https://issues.dlang.org/show_bug.cgi?id=15197

          Issue ID: 15197
           Summary: Allow allocator_list to work with allocators that do
                    not support `expand()`
           Product: D
           Version: D2
          Hardware: All
                OS: All
            Status: NEW
          Keywords: pull
          Severity: enhancement
          Priority: P1
         Component: phobos
          Assignee: nobody@puremagic.com
          Reporter: briancschott@gmail.com

https://github.com/D-Programming-Language/phobos/pull/3689

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