browser.runtime.sendMessage API send large data slowly on Firefox extension - firefox

Question

I use browser.runtime.sendMessage API of firefox extension (firefox 54- 64 bit) send message has large binary data from contentscript to background.
Send message very slowly and make firefox is not responding in 3-5s depending on the data size that contentscript send. Then it works normally and background receive message.
On chrome sendMessage API work quickly and very very smooth.
How can I fix it in firefox?
browser.runtime.sendMessage(tab.id, { name: "sendScreen", data: { screen: screen} })
screen value in object is binary data (array with length ~ 1135609).
In background.js I add listener message:
browser.runtime.onMessage.addListener (message, sender, sendResponse);
Manifest file:
{
"name": "abc",
"background": {
"page": "background.html"
},
"browser_action": {
"default_icon": "icons/icon_19.png",
"default_popup": "login.html",
},
"content_scripts": [
{
"web_accessible_resources": [
"js/contentscripts/Browser.js",
],
"js": [
"js/contentscripts/ContentScript.js"
],
"matches": [
"file://*/*",
"http://*/*",
"https://*/*"
],
"run_at": "document_end",
"all_frames": true
},
{
"js": [
"js/contentscripts/Browser.js",
],
"matches": [
"file://*/*",
"http://*/*",
"https://*/*"
],
"run_at": "document_start",
"all_frames": true
}
],
"icons": {
"16": "icons/icon_16.png",
"19": "icons/icon_19.png"
},
"incognito": "spanning",
"permissions": [
"activeTab",
"tabs",
"http://*/*",
"https://*/*",
"<all_urls>"
],
"content_security_policy": "script-src 'self' 'unsafe-eval'; object-src 'self'"
}

Answer 1

If the bug 1356546 mentioned didn't resolve the issue then file a new firefox bug.
Otherwise you can try to split your data up as was mentioned in comments, that wouldn't reduce the overall time, but it might reduce the affect on UX, or just don't support Firefox until they fix their webextensions bugs.