go1.16 (#14783)

vendor/github.com/blevesearch/vellum/levenshtein/README.md

@@ -0,0 +1,33 @@
+# levenshtein
+levenshtein automaton 
+
+This package makes it fast and simple to build a finite determinic automaton that computes the levenshtein distance from a given string.
+
+# Sample usage:
+
+```
+// build a re-usable builder
+lb := NewLevenshteinAutomatonBuilder(2, false)
+
+origTerm := "couchbasefts"
+dfa := lb.BuildDfa("couchbases", 2)
+ed := dfa.eval([]byte(origTerm))
+if ed.distance() != 2 {
+	log.Errorf("expected distance 2, actual: %d", ed.distance())
+}
+
+```
+
+This implementation is inspired by [blog post](https://fulmicoton.com/posts/levenshtein/) and is intended to be
+a port of original rust implementation: https://github.com/tantivy-search/levenshtein-automata
+
+
+Micro Benchmark Results against the current vellum/levenshtein is as below.
+
+```
+BenchmarkNewEditDistance1-8       	   30000	     52684 ns/op	   89985 B/op	     295 allocs/op
+BenchmarkOlderEditDistance1-8     	   10000	    132931 ns/op	  588892 B/op	     363 allocs/op
+
+BenchmarkNewEditDistance2-8       	   10000	    199127 ns/op	  377532 B/op	    1019 allocs/op
+BenchmarkOlderEditDistance2-8     	    2000	    988109 ns/op	 4236609 B/op	    1898 allocs/op
+```