add support for custom AMF object in streaming clients

[xiuminga]

Summary
This PR adds an optional custom AMF object that is injected during the RTMP connect handshake. It’s designed for large CDN deployments to run targeted stream connectivity checks and diagnostics against specific IPs/nodes by tagging probe metadata in the handshake. Non-RTMP clients safely ignore this parameter.

Changes
• Add customAmfObject to StreamBase.startStream(...) and propagate to clients.
• RTMP: RtmpClient/CommandsManager merge the custom AMF into the connect object (supports optional tcUrl override).
• AmfObject supports dynamic properties.
• MultiStream updated; RTSP/SRT/UDP are no-ops.

Compatibility
• Backward-compatible: when customAmfObject is null, behavior is unchanged; non-RTMP paths ignore it.

[pedroSG94]

Hello,

Thank you for the PR, but It will need a refactor because the way you did to insert new methods to RtmpClient is not correct.

• Only rtmp module and RtmpStreamClient class should be affected by this PR. (create a method in RtmpStreamClient is enougth to get access to the new methods of RtmpClient class).
• In rtmp module change the tcUrl variable is redundant because you already do it using the custom amfObject
• Remove debug logs

Let me know if you have any question or even if you prefer let me do this modifications.

[xiuminga]

Thank you for the review. I’ve updated the PR according to your suggestions, though there may still be issues. If you consider the feature valuable and are willing to make further changes, I’d really appreciate it. Please feel free to modify or close the PR at your discretion.Maybe I should start with an issue🤔

[pedroSG94]

Hello,

Now, the code is close to be fine but I feel that the last commit is not necessary:
da5e4be

• In RtmpClient modify all values has no sense, if you want do it. The way is set an endpoint in startStream with the desired values instead of modify the code that way.
• In CommandsManagerAmf0 you are adding a code logic that is not necessary. You can let the previous way to do it and still get the same result. For example: If you want a custom tcUrl + auth, you can get the auth easy.
  The auth in most of cases is empty, if you set user + password values, you can hardcode it like this:
  https://github.com/pedroSG94/RootEncoder/blob/master/rtmp/src/main/java/com/pedro/rtmp/rtmp/RtmpClient.kt#L452
  https://github.com/pedroSG94/RootEncoder/blob/master/rtmp/src/main/java/com/pedro/rtmp/rtmp/RtmpClient.kt#L455

[pedroSG94]

My code suggestion is this:
https://github.com/pedroSG94/RootEncoder/pull/1917/files

If you are fine with this, let me know it and I can do the merge

[xiuminga]

LGTM. Thanks for the patient guidance and fixes—feel free to merge.

[pedroSG94]

Merged, thank you for the PR