diff --git a/src/node_zlib.cc b/src/node_zlib.cc
index 2c583298d99045..a2acec49c7d96a 100644
--- a/src/node_zlib.cc
+++ b/src/node_zlib.cc
@@ -54,7 +54,6 @@ class ZCtx : public AsyncWrap {
  public:
   ZCtx(Environment* env, Local<Object> wrap, node_zlib_mode mode)
       : AsyncWrap(env, wrap, AsyncWrap::PROVIDER_ZLIB),
-        chunk_size_(0),
         dictionary_(nullptr),
         dictionary_len_(0),
         err_(0),
@@ -179,9 +178,6 @@ class ZCtx : public AsyncWrap {
     ctx->strm_.next_out = out;
     ctx->flush_ = flush;
 
-    // set this so that later on, I can easily tell how much was written.
-    ctx->chunk_size_ = out_len;
-
     if (!async) {
       // sync version
       ctx->env()->PrintSyncTrace();
@@ -625,7 +621,6 @@ class ZCtx : public AsyncWrap {
   static const int kDeflateContextSize = 16384;  // approximate
   static const int kInflateContextSize = 10240;  // approximate
 
-  int chunk_size_;
   Bytef* dictionary_;
   size_t dictionary_len_;
   int err_;