--- a/src/core/ngx_write_chain.c
+++ b/src/core/ngx_write_chain.c
@@ -7,197 +7,44 @@
 #include <ngx_array.h>
 #include <ngx_hunk.h>
 #include <ngx_connection.h>
-#include <ngx_sendv.h>
-#include <ngx_sendfile.h>
+
 
-#include <ngx_write_chain.h>
+ngx_chain_t *(*ngx_write_chain_proc)(ngx_connection_t *c, ngx_chain_t *in);
 
 
 ngx_chain_t *ngx_write_chain(ngx_connection_t *c, ngx_chain_t *in, off_t flush)
 {
-    int           rc, i, last;
-    u_int         flags;
-    char         *prev;
+#if (NGX_EVENT)
+
+    return (*ngx_write_chain_proc)(c, in);
+
+#elif (NGX_EVENT_THREAD)
+
     off_t         sent;
-    ngx_iovec_t  *iov;
-    ngx_array_t   header, trailer;
-    ngx_hunk_t   *file;
-    ngx_chain_t  *ce;
+    ngx_chain_t  *rc;
 
-    ch = in;
-    file = NULL;
-    last = 0;
-
-    ngx_init_array(header, c->pool, 10, sizeof(ngx_iovec_t), NGX_CHAIN_ERROR);
-    ngx_init_array(trailer, c->pool, 10, sizeof(ngx_iovec_t), NGX_CHAIN_ERROR);
+    sent = flush - c->sent;
 
     do {
-        header.nelts = 0;
-        trailer.nelts = 0;
-
-        if (ce->hunk->type & NGX_HUNK_IN_MEMORY) {
-            prev = NULL;
-            iov = NULL;
-
-            /* create iovec and coalesce the neighbouring chain entries */
-            while (ce && (ce->hunk->type & NGX_HUNK_IN_MEMORY))
-            {
-                if (prev == ce->hunk->pos.mem) {
-                    iov->ngx_iov_len += ce->hunk->last.mem - ce->hunk->pos.mem;
+        rc = (*ngx_write_chain_proc)(c, in);
 
-                } else {
-                    ngx_test_null(iov, ngx_push_array(&header),
-                                  NGX_CHAIN_ERROR);
-                    iov->ngx_iov_base = ce->hunk->pos.mem;
-                    iov->ngx_iov_len = ce->hunk->last.mem - ce->hunk->pos.mem;
-                    prev = ce->hunk->last.mem;
-                }
-
-                if (ce->hunk->type & NGX_HUNK_LAST) {
-                    last = 1;
-                }
-
-                ce = ce->next;
-            }
-        }
-
-        if (ce && (ce->hunk->type & NGX_HUNK_FILE)) {
-            file = ce->hunk;
-            ce = ce->next;
-
-            if (ce->hunk->type & NGX_HUNK_LAST) {
-                last = 1;
-            }
+        if (rc == NGX_CHAIN_ERROR && rc == NULL) {
+            return rc;
         }
 
-#if (HAVE_MAX_SENDFILE_IOVEC)
-        if (file && header->nelts > HAVE_MAX_SENDFILE_IOVEC) {
-            rc = ngx_sendv(c->fd, (ngx_iovec_t *) header->elts, header->nelts,
-                           &sent);
-        } else {
-#endif
-            if (ch && ch->hunk->type & NGX_HUNK_IN_MEMORY) {
-                prev = NULL;
-                iov = NULL;
-
-                while (ch && (ch->hunk->type & NGX_HUNK_IN_MEMORY)) {
+    } while (c->thread && flush > c->sent - sent);
 
-                    if (prev == ch->hunk->pos.mem) {
-                        iov->ngx_iov_len +=
-                                        ch->hunk->last.mem - ch->hunk->pos.mem;
-
-                    } else {
-                        ngx_test_null(iov, ngx_push_array(trailer),
-                                      NGX_CHAIN_ERROR);
-                        iov->ngx_iov_base = ch->hunk->pos.mem;
-                        iov->ngx_iov_len =
-                                        ch->hunk->last.mem - ch->hunk->pos.mem;
-                        prev = ch->hunk->last.mem;
-                    }
-
-                    if (ch->hunk->type & NGX_HUNK_LAST) {
-                        last = 1;
-                    }
+#else
 
-                    ch = ch->next;
-                }
-            }
+    ngx_chain_t  *rc;
 
-            if (file) {
-                flags = ngx_sendfile_flags;
-#if (HAVE_SENDFILE_DISCONNECT)
-                if (last && c->close) {
-                    flags |= NGX_SENDFILE_DISCONNECT;
-                }
-#endif
-                rc = ngx_sendfile(c,
-                                  (ngx_iovec_t *) header->elts, header->nelts,
-                                  file->file->fd, file->pos.file,
-                                  (size_t) (file->last.file - file->pos.file),
-                                  (ngx_iovec_t *) trailer->elts, trailer->nelts,
-                                  &sent, flags);
-
-#if (HAVE_AIO_EVENT) && !(HAVE_IOCP_EVENT)
-            } else if (ngx_event_flags & NGX_HAVE_AIO_EVENT) {
-
-                sent = 0;
-                rc = NGX_AGAIN;
-                iov = (ngx_iovec_t *) header->elts;
-                for (i = 0; i < header->nelts; i++) {
-                    rc = ngx_event_aio_write(c, iov[i].ngx_iov_base,
-                                             iov[i].ngx_iov_len);
-
-                    if (rc > 0) {
-                        sent += rc;
-                    } else {
-                        break;
-                    }
+    do {
 
-                    if (rc < (int) iov->ngx_iov_len) {
-                        break;
-                    }
-                }
-#endif
-            } else {
-                rc = ngx_sendv(c, (ngx_iovec_t *) header->elts, header->nelts);
-
-                sent = rc > 0 ? rc: 0;
+        rc = (*ngx_write_chain_proc)(c, in);
 
-#if (NGX_DEBUG_EVENT_WRITE)
-                ngx_log_debug(c->log, "sendv: " OFF_FMT _ sent);
-#endif
-            }
-#if (HAVE_MAX_SENDFILE_IOVEC)
-        }
-#endif
-        if (rc == NGX_ERROR)
-            return (ngx_chain_t *) NGX_ERROR;
-
-        c->sent += sent;
-        flush -= sent;
-
-        for (ch = in; ch; ch = ch->next) {
-
-#if (NGX_DEBUG_EVENT_WRITE)
-            ngx_log_debug(c->log, "event write: %x " QX_FMT " " OFF_FMT _
-                          ch->hunk->type _
-                          ch->hunk->pos.file _
-                          ch->hunk->last.file - ch->hunk->pos.file);
-#endif
+    } while (rc != NGX_CHAIN_ERROR && rc != NULL);
 
-            if (sent >= ch->hunk->last.file - ch->hunk->pos.file) {
-                sent -= ch->hunk->last.file - ch->hunk->pos.file;
-                ch->hunk->pos.file = ch->hunk->last.file;
-
-#if (NGX_DEBUG_EVENT_WRITE)
-                ngx_log_debug(c->log, "event write: " QX_FMT " 0 " OFF_FMT _
-                              ch->hunk->pos.file _ sent);
-#endif
-
-/*
-                if (ch->hunk->type & NGX_HUNK_LAST)
-                   break;
-*/
-
-                continue;
-            }
+    return rc;
 
-            ch->hunk->pos.file += sent;
-
-#if (NGX_DEBUG_EVENT_WRITE)
-            ngx_log_debug(c->log, "event write: " QX_FMT " " OFF_FMT _
-                          ch->hunk->pos.file _
-                          ch->hunk->last.file - ch->hunk->pos.file);
 #endif
-
-            break;
-        }
-
-    /* flush hunks if threaded state */
-    } while (c->write->context && flush > 0);
-
-    ngx_destroy_array(&trailer);
-    ngx_destroy_array(&header);
-
-    return ch;
 }