diff --git a/lib/down/chunked_io.rb b/lib/down/chunked_io.rb
index <HASH>..<HASH> 100644
--- a/lib/down/chunked_io.rb
+++ b/lib/down/chunked_io.rb
@@ -36,6 +36,8 @@ module Down
       @rewindable = rewindable
       @buffer     = nil
       @position   = 0
+      @next_chunk = nil
+      @closed     = false
 
       retrieve_chunk # fetch first chunk so that we know whether the file is empty
     end
diff --git a/test/support/warnings.rb b/test/support/warnings.rb
index <HASH>..<HASH> 100644
--- a/test/support/warnings.rb
+++ b/test/support/warnings.rb
@@ -1,3 +1,4 @@
 require "warning"
 
+Warning.process('', /instance variable @\w+ not initialized/ => :raise)
 Warning.ignore(/interpreted as argument prefix/, Gem::Specification.find_by_name("http-parser").load_paths.first)
Remove uninitialized @next_chunk and @closed warnings

Fixes #<I>