diff --git a/lib/zlib/inffast.js b/lib/zlib/inffast.js
index 1bcae7f..a419f65 100644
--- a/lib/zlib/inffast.js
+++ b/lib/zlib/inffast.js
@@ -52,7 +52,8 @@ module.exports = function inflate_fast(strm, start) {
   var wsize;                  /* window size or zero if not using window */
   var whave;                  /* valid bytes in the window */
   var wnext;                  /* window write index */
-  var window;                 /* allocated sliding window, if wsize != 0 */
+  // Use `s_window` instead `window`, avoid conflict with instrumentation tools
+  var s_window;               /* allocated sliding window, if wsize != 0 */
   var hold;                   /* local strm.hold */
   var bits;                   /* local strm.bits */
   var lcode;                  /* local strm.lencode */
@@ -86,7 +87,7 @@ module.exports = function inflate_fast(strm, start) {
   wsize = state.wsize;
   whave = state.whave;
   wnext = state.wnext;
-  window = state.window;
+  s_window = state.window;
   hold = state.hold;
   bits = state.bits;
   lcode = state.lencode;
@@ -204,13 +205,13 @@ module.exports = function inflate_fast(strm, start) {
 //#endif
               }
               from = 0; // window index
-              from_source = window;
+              from_source = s_window;
               if (wnext === 0) {           /* very common case */
                 from += wsize - op;
                 if (op < len) {         /* some from window */
                   len -= op;
                   do {
-                    output[_out++] = window[from++];
+                    output[_out++] = s_window[from++];
                   } while (--op);
                   from = _out - dist;  /* rest from output */
                   from_source = output;
@@ -222,14 +223,14 @@ module.exports = function inflate_fast(strm, start) {
                 if (op < len) {         /* some from end of window */
                   len -= op;
                   do {
-                    output[_out++] = window[from++];
+                    output[_out++] = s_window[from++];
                   } while (--op);
                   from = 0;
                   if (wnext < len) {  /* some from start of window */
                     op = wnext;
                     len -= op;
                     do {
-                      output[_out++] = window[from++];
+                      output[_out++] = s_window[from++];
                     } while (--op);
                     from = _out - dist;      /* rest from output */
                     from_source = output;
@@ -241,7 +242,7 @@ module.exports = function inflate_fast(strm, start) {
                 if (op < len) {         /* some from window */
                   len -= op;
                   do {
-                    output[_out++] = window[from++];
+                    output[_out++] = s_window[from++];
                   } while (--op);
                   from = _out - dist;  /* rest from output */
                   from_source = output;