CSHARP-2595: Fix initialization on .NET Core 3.0 preview 4.

[KonH]

I have faced with problem after upgrade to .NET Core 3.0 preview 4 in my project, this line starts throwing an exception:

mongo-csharp-driver/src/MongoDB.Bson/Serialization/BsonClassMap.cs

Line 40 in 660658d

private static readonly MethodInfo __getUninitializedObjectMethodInfo =

This change cover .NET Framework and .NET Core ways to get System.Runtime.Serialization.FormatterServices type instance.

I'm don't sure how to write a proper test for that case but test it manually on .NET Framework 4.5.2, .NET Core 2.1, 2.2 and 3.0.

This PR is related to already created jira task with a proposal, which was implemented - https://jira.mongodb.org/browse/CSHARP-2595.

[Malavos]

Will someone accept this PR? It seems that it fixes the problem.

[mostafa-tag]

@KonH thanks for this fix , When it will be rolled out via nugget on 2.8.x branch ?

[KonH]

@KonH thanks for this fix , When it will be rolled out via nugget on 2.8.x branch ?

I wait until somebody accept it. Or I need another PR for it?

[vincentkam]

Hello @KonH , thank you for your PR! Another PR isn't necessary at this point. Given the imminent release of .NET Core 3.0 in the second half of 2019, we will be re-triaging and taking another look at this issue extremely soon.

[Malavos]

@vincentkam thank you for the clarification. We will await then the update.

[rstam]

We're working on this change, with some additional changes to retain compatibility with older versions of .NET Core.

If interested, see:

rstam#110

[dewelloper]

What will done to my project i trust this 3.0 and i have upgraded my framework. Now what i will do..
Ayşegülün suçu ne?

Everything worked grate after downgrading core 3.0 to 2.2

[neil-119]

Thanks @KonH , your patch worked. I tried the latest master version too, since they mentioned that it passed code review and was being merged in, but that one was still throwing exceptions so I tried yours.

[jacodv]

Hi @KonH, I have to port to preview 5 and this issue is causing a break in my tests. Is there a way that I can get a signed version with the fix in it to continue my upgrade?

[KonH]

@jacodv, unfortunately, I don't know how it can be done (if possible). I think you need to wait for the merge (and according to conversion, #110 can be merged instead of this one). Comments from more involved people can be helpful.

[jacodv]

Thanks @KonH , I will branch off and continue with other porting until 2.8.1 is out

[rstam]

Squashed, rebased and merged.

[DavidRHale]

@rstam Any idea when 2.8.1 will be released with this change?
Many thanks

[rstam]

2.8.1 was released today, May 15, 2019.