A bleve based Percolator.
Traditionally search engines search many documents with one query. A Percolator runs many queries against one document and acts on the matched query/queries.
Note: This turns out to be a really bad idea in bleve. They seem to have attached the searchers to the Query rather then the index, like Lucene does. This creates a massive number of allocs, causing the GC to pause in a bad way.
MIT