QUIC: coalesce neighbouring stream send buffers. Previously a single STREAM frame was created for each buffer in stream output chain which is wasteful with respect to memory. The following changes were made in the stream send code: - ngx_quic_stream_send_chain() no longer calls ngx_quic_stream_send() and got a separate implementation that coalesces neighbouring buffers into a single frame - the new ngx_quic_stream_send_chain() respects the limit argument, which fixes sendfile_max_chunk and limit_rate - ngx_quic_stream_send() is reimplemented to call ngx_quic_stream_send_chain() - stream frame size limit is moved out to a separate function ngx_quic_max_stream_frame() - flow control is moved out to a separate function ngx_quic_max_stream_flow() - ngx_quic_stream_send_chain() is relocated next to ngx_quic_stream_send()

/*
 * Copyright (C) Maxim Dounin
 * Copyright (C) Nginx, Inc.
 */


#include <ngx_config.h>
#include <ngx_core.h>


#if (NGX_HAVE_DLOPEN)

char *
ngx_dlerror(void)
{
    char  *err;

    err = (char *) dlerror();

    if (err == NULL) {
        return "";
    }

    return err;
}

#endif