Fix memory leak from undisposed sockets and event handler retention during server restart - #3608

Type 'SubscriptionContainer' can be sealed because it has no subtypes in its containing assembly and is not externally visible (https://learn.microsoft.com/dotnet/fundamentals/code-analysis/quality-rules/ca1852)

Type 'SubscriptionContainer' can be sealed because it has no subtypes in its containing assembly and is not externally visible (https://learn.microsoft.com/dotnet/fundamentals/code-analysis/quality-rules/ca1852)

Type 'SubscriptionContainer' can be sealed because it has no subtypes in its containing assembly and is not externally visible (https://learn.microsoft.com/dotnet/fundamentals/code-analysis/quality-rules/ca1852)

Type 'SubscriptionContainer' can be sealed because it has no subtypes in its containing assembly and is not externally visible (https://learn.microsoft.com/dotnet/fundamentals/code-analysis/quality-rules/ca1852)

Type 'SubscriptionContainer' can be sealed because it has no subtypes in its containing assembly and is not externally visible (https://learn.microsoft.com/dotnet/fundamentals/code-analysis/quality-rules/ca1852)

Type 'SubscriptionContainer' can be sealed because it has no subtypes in its containing assembly and is not externally visible (https://learn.microsoft.com/dotnet/fundamentals/code-analysis/quality-rules/ca1852)

Type 'SubscriptionContainer' can be sealed because it has no subtypes in its containing assembly and is not externally visible (https://learn.microsoft.com/dotnet/fundamentals/code-analysis/quality-rules/ca1852)

Type 'SubscriptionContainer' can be sealed because it has no subtypes in its containing assembly and is not externally visible (https://learn.microsoft.com/dotnet/fundamentals/code-analysis/quality-rules/ca1852)

Type 'SubscriptionContainer' can be sealed because it has no subtypes in its containing assembly and is not externally visible (https://learn.microsoft.com/dotnet/fundamentals/code-analysis/quality-rules/ca1852)

Type 'SubscriptionContainer' can be sealed because it has no subtypes in its containing assembly and is not externally visible (https://learn.microsoft.com/dotnet/fundamentals/code-analysis/quality-rules/ca1852)