If a node cannot allocate a 128 kB it is already in a very bad shape, so
there isn't much value in trying to recover by attempting smaller
allocations and it just adds more complexity to the segment allocation.
It actually may be better to let some requests fail and give the node a
chance to recover rather than trying to use every last byte of free
memory and end up with bad_alloc in a noexcept context.
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