Add C# language bindings for payjoin-ffi

[chavic]

This work in progress adds C# bindings and implements tests following the pattern in the other languages

[coveralls]

Pull Request Test Coverage Report for Build 22036417669

Details

• 0 of 0 changed or added relevant lines in 0 files are covered.
• No unchanged relevant lines lost coverage.
• Overall coverage remained the same at 83.18%

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Totals
Change from base Build 22022393890:	0.0%
Covered Lines:	10217
Relevant Lines:	12283

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💛 - Coveralls

[DanGould]

BOOYEAH

I like the direction this is going.

[DanGould]

Is net8.0 the most common target? I'm very curious what the actual needs of a BTCpayServer plugin or Strike are, because I've dealt with incompatibility issue here, albeit years ago.

[DanGould]

it can: https://blog.btcpayserver.org/btcpay-server-1-12-0/#upgrade-to-net-8. Strike is likely ahead because they don't need to support a bunch of open source stuff.

[chavic]

I see, any idea which specific runtime they're on?

I did a quick check beforehand to target the most common runtime right now...

Gonna look loser into the Strike repos specifically

[DanGould]

strike very likely on net8.0. probably private repos. i'll ask their team

[ValeraFinebits]

I've been working on an experimental C# bindings prototype in my fork (ValeraFinebits#1) while building a BTCPayServer Payjoin plugin, mainly to explore integration possibilities.

This PR aligns closely with what I implemented there, and in my local testing everything works as expected. I'll migrate my plugin to these upstream bindings and share any issues or improvement ideas as I go.

[DanGould]

Hi @ValeraFinebits I saw your PR open and close. Thanks bigly for writing us updates here. Very eager to see what that plugin can do and challenges hooking it up to BTCPay via the plugin framework.