new file mode 100644
--- /dev/null
+++ b/src/os/unix/ngx_aio_write.c
@@ -0,0 +1,117 @@
+
+/*
+ * Copyright (C) Igor Sysoev
+ */
+
+
+#include <ngx_config.h>
+#include <ngx_core.h>
+#include <ngx_event.h>
+#include <ngx_aio.h>
+
+#if (HAVE_KQUEUE)
+#include <ngx_kqueue_module.h>
+#endif
+
+
+/*
+ * the ready data requires 3 syscalls:
+ *     aio_write(), aio_error(), aio_return()
+ * the non-ready data requires 4 (kqueue) or 5 syscalls:
+ *     aio_write(), aio_error(), notifiction, aio_error(), aio_return()
+ *                               timeout, aio_cancel(), aio_error()
+ */
+
+ssize_t ngx_aio_write(ngx_connection_t *c, u_char *buf, size_t size)
+{
+    int           n;
+    ngx_event_t  *wev;
+
+    wev = c->write;
+
+    if (!wev->ready) {
+        return NGX_AGAIN;
+    }
+
+    ngx_log_debug1(NGX_LOG_DEBUG_EVENT, wev->log, 0,
+                   "aio: wev->complete: %d", wev->complete);
+
+    if (!wev->complete) {
+        ngx_memzero(&wev->aiocb, sizeof(struct aiocb));
+
+        wev->aiocb.aio_fildes = c->fd;
+        wev->aiocb.aio_buf = buf;
+        wev->aiocb.aio_nbytes = size;
+
+#if (HAVE_KQUEUE)
+        wev->aiocb.aio_sigevent.sigev_notify_kqueue = ngx_kqueue;
+        wev->aiocb.aio_sigevent.sigev_notify = SIGEV_KEVENT;
+        wev->aiocb.aio_sigevent.sigev_value.sigval_ptr = wev;
+#endif
+
+        if (aio_write(&wev->aiocb) == -1) {
+            ngx_log_error(NGX_LOG_CRIT, wev->log, ngx_errno,
+                          "aio_write() failed");
+            return NGX_ERROR;
+        }
+
+        ngx_log_debug0(NGX_LOG_DEBUG_EVENT, wev->log, 0, "aio_write: OK");
+
+        wev->active = 1;
+        wev->ready = 0;
+    }
+
+    wev->complete = 0;
+
+    n = aio_error(&wev->aiocb);
+    if (n == -1) {
+        ngx_log_error(NGX_LOG_CRIT, wev->log, ngx_errno, "aio_error() failed");
+        wev->error = 1;
+        return NGX_ERROR;
+    }
+
+    if (n != 0) {
+        if (n == NGX_EINPROGRESS) {
+            if (wev->ready) {
+                ngx_log_error(NGX_LOG_ALERT, wev->log, n,
+                              "aio_write() still in progress");
+                wev->ready = 0;
+            }
+            return NGX_AGAIN;
+        }
+
+        ngx_log_error(NGX_LOG_CRIT, wev->log, n, "aio_write() failed");
+        wev->error = 1;
+        wev->ready = 0;
+
+#if 1
+        n = aio_return(&wev->aiocb);
+        if (n == -1) {
+            ngx_log_error(NGX_LOG_ALERT, wev->log, ngx_errno,
+                          "aio_return() failed");
+        }
+
+        ngx_log_error(NGX_LOG_CRIT, wev->log, n, "aio_return() %d", n);
+#endif
+
+        return NGX_ERROR;
+    }
+
+    n = aio_return(&wev->aiocb);
+    if (n == -1) {
+        ngx_log_error(NGX_LOG_ALERT, wev->log, ngx_errno,
+                      "aio_return() failed");
+
+        wev->error = 1;
+        wev->ready = 0;
+        return NGX_ERROR;
+    }
+
+
+    ngx_log_debug1(NGX_LOG_DEBUG_EVENT, wev->log, 0, "aio_write: %d", n);
+
+    wev->active = 0;
+    wev->ready = 1;
+
+    return n;
+}