Please consider adding WriteToServer(Span<T> elements) method

[toomasz]

It would be nice to have support for new .NET Span api.

[ErikEJ]

?? PRs accepted!

[toomasz]

I just tried to investigate if it's easy to add it. Unfortunately it's not.
First I would have to bump C# version to 7.3 and .net framework to 4.7.1 since Span is ref struct, not sure if thats acceptable for your project.
Then one would have to copy

SqlCeBulkCopy/src/SqlCeBulkCopy.cs

Line 257 in 8e06ce8

private void WriteToServer(ISqlCeBulkCopyInsertAdapter adapter)

as adapter implementing ISqlCeBulkCopyInsertAdapter cannot be used for Span(Span is ref struct, in can only be member of ref struct which cannot implement interface, its stack only structure)
It seems heavy refactoring would be needed here.

[ErikEJ]

1: You can just create a new csproj (as a copy) and target it to .NET 4.7.1

2: Since this is a private method, you can just implement using Span, no need to touch the interface or it's implementaton