diff --git a/async.c b/async.c
index 04a4245..6821755 100644
--- a/async.c
+++ b/async.c
@@ -38,8 +38,17 @@ void __redisAppendCommand(redisContext *c, char *cmd, size_t len);
 
 static redisAsyncContext *redisAsyncInitialize(redisContext *c) {
     redisAsyncContext *ac = realloc(c,sizeof(redisAsyncContext));
-    /* Set all bytes in the async part of the context to 0 */
-    memset(ac+sizeof(redisContext),0,sizeof(redisAsyncContext)-sizeof(redisContext));
+    ac->err = 0;
+    ac->errstr = NULL;
+    ac->data = NULL;
+    ac->evAddRead = NULL;
+    ac->evDelRead = NULL;
+    ac->evAddWrite = NULL;
+    ac->evDelWrite = NULL;
+    ac->evCleanup = NULL;
+    ac->onDisconnect = NULL;
+    ac->replies.head = NULL;
+    ac->replies.tail = NULL;
     return ac;
 }
 
diff --git a/async.h b/async.h
index d0a99da..be3a7a9 100644
--- a/async.h
+++ b/async.h
@@ -58,6 +58,9 @@ typedef struct redisAsyncContext {
     int err;
     char *errstr;
 
+    /* Not used by hiredis */
+    void *data;
+
     /* Called when the library expects to start reading/writing.
      * The supplied functions should be idempotent. */
     void (*evAddRead)(void *privdata);
@@ -65,7 +68,6 @@ typedef struct redisAsyncContext {
     void (*evAddWrite)(void *privdata);
     void (*evDelWrite)(void *privdata);
     void (*evCleanup)(void *privdata);
-    void *data;
 
     /* Called when either the connection is terminated due to an error or per
      * user request. The status is set accordingly (REDIS_OK, REDIS_ERR). */