.. warning::

  Deprecated.  Use `nghttp2_submit_request2()` instead.

Submits HEADERS frame and optionally one or more DATA frames.

The *pri_spec* is ignored.

The *nva* is an array of name/value pair :type:`nghttp2_nv` with
*nvlen* elements.  The application is responsible to include
required pseudo-header fields (header field whose name starts with
":") in *nva* and must place pseudo-headers before regular header
fields.

This function creates copies of all name/value pairs in *nva*.  It
also lower-cases all names in *nva*.  The order of elements in
*nva* is preserved.  For header fields with
:enum:`nghttp2_nv_flag.NGHTTP2_NV_FLAG_NO_COPY_NAME` and
:enum:`nghttp2_nv_flag.NGHTTP2_NV_FLAG_NO_COPY_VALUE` are set,
header field name and value are not copied respectively.  With
:enum:`nghttp2_nv_flag.NGHTTP2_NV_FLAG_NO_COPY_NAME`, application
is responsible to pass header field name in lowercase.  The
application should maintain the references to them until
:type:`nghttp2_on_frame_send_callback` or
:type:`nghttp2_on_frame_not_send_callback` is called.

HTTP/2 specification has requirement about header fields in the
request HEADERS.  See the specification for more details.

If *data_prd* is not ``NULL``, it provides data which will be sent
in subsequent DATA frames.  In this case, a method that allows
request message bodies
(https://tools.ietf.org/html/rfc7231#section-4) must be specified
with ``:method`` key in *nva* (e.g. ``POST``).  This function does
not take ownership of the *data_prd*.  The function copies the
members of the *data_prd*.  If *data_prd* is ``NULL``, HEADERS have
END_STREAM set.  The *stream_user_data* is data associated to the
stream opened by this request and can be an arbitrary pointer,
which can be retrieved later by
`nghttp2_session_get_stream_user_data()`.

This function returns assigned stream ID if it succeeds, or one of
the following negative error codes:

:enum:`nghttp2_error.NGHTTP2_ERR_NOMEM`
    Out of memory.
:enum:`nghttp2_error.NGHTTP2_ERR_STREAM_ID_NOT_AVAILABLE`
    No stream ID is available because maximum stream ID was
    reached.
:enum:`nghttp2_error.NGHTTP2_ERR_PROTO`
    The *session* is server session.

.. warning::

  This function returns assigned stream ID if it succeeds.  But
  that stream is not created yet.  The application must not submit
  frame to that stream ID before
  :type:`nghttp2_before_frame_send_callback` is called for this
  frame.  This means `nghttp2_session_get_stream_user_data()` does
  not work before the callback.  But
  `nghttp2_session_set_stream_user_data()` handles this situation
  specially, and it can set data to a stream during this period.