E2E Test Coverage Part 2 & Add .NET 9.0 Support

[pglombardo]

In the ramp up to v1, we are putting in thorough E2E tests to cover all parts of the protocol and client.

Besides extended tests, this PR includes the following fixes:

1. Updated build system
2. Add support for .NET 9.0

.NET 6.0 has hit end of life on November 12, 2024 &&
.NET 7.0 has hit end of support on May 14, 2024
https://dotnet.microsoft.com/en-us/platform/support/policy/dotnet-core

Description

Related Issue

Type of Change

• 📚 Examples / docs / tutorials / dependencies update
• 🔧 Bug fix (non-breaking change which fixes an issue)
• 🥂 Improvement (non-breaking change which improves an existing feature)
• 🚀 New feature (non-breaking change which adds functionality)
• 💥 Breaking change (fix or feature that would cause existing functionality to change)
• 🔐 Security fix

Checklist

• I've written tests (if applicable) for all new methods and classes that I created. (rake test)
• I've added documentation as necessary so users can easily use and understand this feature/fix.