diff --git a/lib/airbrake-ruby/tdigest.rb b/lib/airbrake-ruby/tdigest.rb
index <HASH>..<HASH> 100644
--- a/lib/airbrake-ruby/tdigest.rb
+++ b/lib/airbrake-ruby/tdigest.rb
@@ -247,7 +247,7 @@ module Airbrake
     end
 
     def to_a
-      @centroids.map { |_, c| c }
+      @centroids.each_value.to_a
     end
 
     # rubocop:disable Metrics/PerceivedComplexity, Metrics/MethodLength
tdigest: refactor #to_a to use more idiomatic Ruby