Issue with hls.stringify for cloned hls object

[jagadishkamathk]

When an HLS object is cloned via JSON.parse(JSON.stringify(manifest)), the resulting object cannot be stringified. The issue lies in

1. programDateTime field - This gets converted into string. Need to be converted back to Date before stringify
2. IV - The buffer gets converted to object. Should be converted back to buffer before stringify
   It would be great if the stringify function can handle this internally more efficiently

Here is the sample code to demonstrate this

const hls   =  require("hls-parser")
var input = "#EXTM3U \n" + 
            "#EXT-X-VERSION:5 \n" + 
            "#EXT-X-MEDIA-SEQUENCE:0 \n" + 
            "#EXT-X-TARGETDURATION:4 \n" + 
            "#EXT-X-PROGRAM-DATE-TIME:2021-08-02T07:24:22.997000+00:00 \n" + 
            "#EXT-X-KEY:METHOD=AES-128,URI=\"enc.key\"" + ",IV=0x0000000000000000000000000000044A \n" + 
            "#EXTINF:4, \n" + 
            "0.ts \n" + 
            "#EXTINF:4, \n" + 
            "1.ts \n" + 
            "#EXTINF:4, \n" + 
            "2.ts";
var manifest  = hls.parse(input);
var manifest2 = JSON.parse(JSON.stringify(manifest));
var output = hls.stringify(manifest2);