.NET Core 3.0 migration error IAsyncEnumerable<T> exists in both System.Interactive.Async and System.Runtime

The suggestion from Panatiotis works, I added the reference to Microsoft.EntityFrameworkCore 3.0 and it worked. This reference was not needed in .NET Core 2.2 for my situation.

As one who stumbled upon this on .NET Core 2.2 but wasn't migrating to 3+, I found another solution on the same issue refereced before. Project file referenced was modified since this comment, so here's a direct link.

In my case I added this target to project file:

<Target Name="AddAssemblyAliasToReactiveAsync"
        AfterTargets="ResolveAssemblyReferences"
        Condition="'$(TargetFramework)' == 'netcoreapp2.2'">
  <ItemGroup>
    <ReferencePath Condition=" '%(FileName)' == 'System.Interactive.Async' ">
      <Aliases>reactive</Aliases>
    </ReferencePath>
  </ItemGroup>
</Target>