syntax_data: {"ast_node_type":"other","tokens":[{"end":6,"kind":"keyword","start":0,"text":"//"}]}
source_snippet:     //
context_before:     // Seek *to* every possible `SeekTarget` *from* every possible `SeekTarget`.
context_after:     // By resetting the cursor to `from` each time it changes, we end up checking some edges twice.