Render first page before download is complete (linear / web optimized)

Without Linear PDF feature most of the PDFs (especially with pictures) loads very slowly. According to the console's information, pdf.js version of this plug-in is 2.1.266, but the current version of pdf.js is 2.5.179, which supports pdf.js.

Steps to reproduce

1. Load any Linearized PDF to storage (or use my PDF)
2. Check how slowly it loads
3. Upload to any host and check how fast your browser can load the first page, while loading other pages

Expected behaviour

Linear PDF support in PDF viewer.

Actual behaviour

Lack of Linear PDF support, and slow loadings...

Server configuration

Operating system: Linux 5.4.0-26-generic #30-Ubuntu SMP Mon Apr 20 16:58:30 UTC 2020 x86_64

Web server: nginx/1.17.10 (fpm-fcgi)

Database: mysql 8.0.20

PHP version: 7.4.7
Modules loaded: Core, date, libxml, openssl, pcre, zlib, filter, hash, Reflection, SPL, session, standard, sodium, cgi-fcgi, mysqlnd, PDO, xml, calendar, ctype, curl, dom, mbstring, FFI, fileinfo, ftp, gd, gettext, gmp, iconv, igbinary, imagick, intl, json, exif, msgpack, mysqli, pdo_mysql, Phar, posix, readline, shmop, SimpleXML, sockets, sysvmsg, sysvsem, sysvshm, tokenizer, xmlreader, xmlwriter, xsl, zip, memcached, Zend OPcache

Nextcloud version: 18.0.7 - 18.0.7.1

Where did you install Nextcloud from: from official website

List of activated apps:

Enabled:

• accessibility: 1.4.0
• activity: 2.11.0
• bruteforcesettings: 1.6.0
• cloud_federation_api: 1.1.0
• comments: 1.8.0
• dav: 1.14.0
• federatedfilesharing: 1.8.0
• federation: 1.8.0
• files: 1.13.1
• files_pdfviewer: 1.7.0
• files_rightclick: 0.15.2
• files_sharing: 1.10.1
• files_trashbin: 1.8.0
• files_versions: 1.11.0
• files_videoplayer: 1.7.0
• firstrunwizard: 2.7.0
• issuetemplate: 0.6.0
• logreader: 2.3.0
• lookup_server_connector: 1.6.0
• nextcloud_announcements: 1.7.0
• notifications: 2.6.0
• oauth2: 1.6.0
• password_policy: 1.8.0
• photos: 1.0.0
• privacy: 1.2.0
• provisioning_api: 1.8.0
• recommendations: 0.6.0
• serverinfo: 1.8.0
• settings: 1.0.0
• sharebymail: 1.8.0
• support: 1.1.1
• survey_client: 1.6.0
• systemtags: 1.8.0
• text: 2.0.0
• theming: 1.9.0
• twofactor_backupcodes: 1.7.0
• updatenotification: 1.8.0
• viewer: 1.2.0
• workflowengine: 2.0.0
  Disabled:
• admin_audit
• encryption
• files_external
• user_ldap

Nextcloud configuration:

{
"instanceid": "REMOVED SENSITIVE VALUE",
"passwordsalt": "REMOVED SENSITIVE VALUE",
"secret": "REMOVED SENSITIVE VALUE",
"trusted_domains": [
"cloud.sonic.fan"
],
"datadirectory": "REMOVED SENSITIVE VALUE",
"dbtype": "mysql",
"version": "18.0.7.1",
"overwrite.cli.url": "https://cloud.sonic.fan",
"dbname": "REMOVED SENSITIVE VALUE",
"dbhost": "REMOVED SENSITIVE VALUE",
"dbport": "",
"dbtableprefix": "oc_",
"mysql.utf8mb4": true,
"dbuser": "REMOVED SENSITIVE VALUE",
"dbpassword": "REMOVED SENSITIVE VALUE",
"installed": true,
"memcache.local": "\OC\Memcache\Memcached",
"memcache.distributed": "\OC\Memcache\Memcached",
"memcached_servers": [
[
"localhost",
11211
]
],
"theme": "",
"loglevel": 2,
"maintenance": false,
"updater.secret": "REMOVED SENSITIVE VALUE",
"updater.release.channel": "stable"
}

Client configuration

Browser: Mozilla/5.0 (Windows NT 10.0; Win64; x64; rv:78.0) Gecko/20100101 Firefox/78.0

Operating system: Windows 10 Pro x64

Logs

Nextcloud log (data/owncloud.log)

There is no log for this.

Browser log

Version string from console: "(PDF.js: 2.1.266)"

No repository file or test is named in the report. Start by locating the PDF.js integration and its loading path, using the reported 2.1.266 version and linearized PDFs as the baseline. Done means the first page renders before the complete PDF download while later pages continue loading.