Module radix_tree 

2026-09-25: The radix-tree prefix cache (PrefixCache implementation): KV block reuse plus the SSM snapshot index.

Token sequences are chunked at block_size; each tree node stores one KV block. A lookup walks block-aligned chunks and returns the cached block indices, then asks the snapshot index for the deepest SSM snapshot within the matched prefix.

Owner: cache. Invariants:

• The tree and the snapshot index are behind separate mutexes, and no method holds both: inner is released before snapshot_index is taken.
• One radix root per adapter_id, so no lookup returns another adapter’s blocks.

Structs

RadixTree

2026-09-25: The radix-tree prefix cache. SSM snapshots live in a separate SsmSnapshotIndex, so evicting tree nodes does not remove them.