Container of free blocks that use minimal usable space.

The container used to hold the blocks is a singly-linked list. As a result, it is able to store free blocks as small as sizeof(void*). Insertion and removal of an unspecified block is O(1). Removal internal::of a specific block is O(n) since the whole list may need to be walked to find the block. As such, this bucket type is useful for pools of blocks of a single size.