Description
Background and motivation
In #75759 we approved two APIs that use a callback mechanism for encoding when using AsnWriter. Both of the added methods return a TReturn.
When wiring this in through the Libraries, there are several places that look like this:
They modify some state that gets passed in, but don't need to return anything, which results in a return (object?)null.
We should overload Encode to accept an Action callback and return void.
API Proposal
namespace System.Formats.Asn1;
public partial class AsnWriter {
#if NET9_0_OR_GREATER
public void Encode<TState>(
TState state,
Action<TState, ReadOnlySpan<byte>> encodeCallback) where TState : allows ref struct;
#endif
}API Usage
From the example above, that would become a nicer-looking:
inner.Encode(writer, static (writer, encoded) =>
{
writer.WriteBitString(encoded);
});Alternative Designs
There is, yet another, overload we could add - which is one that accepts no state and returns nothing. I don't know how useful that is. That would imply that global state is being modified, or something captured.
That would look like:
public void Encode(Action<ReadOnlySpan<byte>> encodeCallback);But I see little utility in it. It can be added for symmetry if that is important.
Risks
No response