Stores local settings and submits SETTINGS frame.  The *iv* is the
pointer to the array of :type:`nghttp2_settings_entry`.  The *niv*
indicates the number of :type:`nghttp2_settings_entry`.

The *flags* is currently ignored and should be
:enum:`nghttp2_flag.NGHTTP2_FLAG_NONE`.

This function does not take ownership of the *iv*.  This function
copies all the elements in the *iv*.

While updating individual stream's local window size, if the window
size becomes strictly larger than NGHTTP2_MAX_WINDOW_SIZE,
RST_STREAM is issued against such a stream.

SETTINGS with :enum:`nghttp2_flag.NGHTTP2_FLAG_ACK` is
automatically submitted by the library and application could not
send it at its will.

This function returns 0 if it succeeds, or one of the following
negative error codes:

:enum:`nghttp2_error.NGHTTP2_ERR_INVALID_ARGUMENT`
    The *iv* contains invalid value (e.g., initial window size
    strictly greater than (1 << 31) - 1.
:enum:`nghttp2_error.NGHTTP2_ERR_NOMEM`
    Out of memory.