Added primitive flow control mechanisms. + MAX_STREAM_DATA frame is sent when recv() is performed on stream The new value is a sum of total bytes received by stream + free space in a buffer; The sending of MAX_STREM_DATA frame in response to STREAM_DATA_BLOCKED frame is adjusted to follow the same logic as above. + MAX_DATA frame is sent when total amount of received data is 2x of current limit. The limit is doubled. + Default values of transport parameters are adjusted to more meaningful values: initial stream limits are set to quic buffer size instead of unrealistically small 255. initial max data is decreased to 16 buffer sizes, in an assumption that this is enough for a relatively short connection, instead of randomly chosen big number. All this allows to initiate a stable flow of streams that does not block on stream/connection limits (tested with FF 77.0a1 and 100K requests)

/*
 * Copyright (C) Igor Sysoev
 * Copyright (C) Nginx, Inc.
 */


#ifndef _NGX_MAIL_IMAP_MODULE_H_INCLUDED_
#define _NGX_MAIL_IMAP_MODULE_H_INCLUDED_


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


typedef struct {
    size_t       client_buffer_size;

    ngx_str_t    capability;
    ngx_str_t    starttls_capability;
    ngx_str_t    starttls_only_capability;

    ngx_uint_t   auth_methods;

    ngx_array_t  capabilities;
} ngx_mail_imap_srv_conf_t;


void ngx_mail_imap_init_session(ngx_mail_session_t *s, ngx_connection_t *c);
void ngx_mail_imap_init_protocol(ngx_event_t *rev);
void ngx_mail_imap_auth_state(ngx_event_t *rev);
ngx_int_t ngx_mail_imap_parse_command(ngx_mail_session_t *s);


extern ngx_module_t  ngx_mail_imap_module;


#endif /* _NGX_MAIL_IMAP_MODULE_H_INCLUDED_ */