Network Information Api polyfill

An attempt to create polyfill for this specification. Polyfill is based on pinging
some url and latency analysis. These are pretty rough measurements. But better than nothing.

Usage

``bash
npm i -S network-information-api-polyfill
`

or just

`html

`

Then you need to initialize it

`js
new NetworkInformationApiPolyfill().then(connection => {
console.log(connection); // or navigator.connection

connection.addEventListener('change', e => {
console.log('change', e);
});
});
`

Polyfill must do the first request, to get information about network. So you can't use it synchronously, only using
promise.

$3

You can pass options during initialization:
`js
new NetworkInformationApiPolyfill({
// here
});
`

##### pingMaxTimeout
Type: number
Default: 5000

Timeout of request. After this time, the network will be considered unavailable (navigator.connection.type === 'none).

##### pingFrequency
Type: number
Default: 6000

A frequency of pinging.

##### pingUrl
Type: string
Default: ${location.protocol}//network-information-api.surge.sh/1b.txt

An url, that will be pinged. It is strongly recommended to have your own address.
It improves the accuracy of measurements in relation to the user of your service.

$3


If you have CSP rules, and you don't want own pingUrl, you must add url
network-information-api.surge.sh to rule connect-src`.