Xamarinのエラー

Xamarinのエラー

Warning: All projects referencing MyProject.csproj must install nuget package Microsoft.Bcl.Build. For more information, see http://go.microsoft.com/fwlink/?LinkID=317569. (MyProject.Droid)

visual studio - warning : All projects referencing MyProject.csproj must install nuget package Microsoft.Bcl.Build - Stack Overflow

https://forums.xamarin.com/discussion/43098/microsoft-bcl-build-reference-warning