[API Proposal]: ReadOnlySequence<byte> handling by System.Text.Json source generator

[paulomorgado]

Background and motivation

In .NET 8.0, System.Text.Json source generator generates code to JSON serialize ReadOnlyMemory<byte> values the same way as byte[].

To avoid extra allocations, it would be nice to be able to JSON serialize ReadOnlySequence<byte> the same way.

Currently, the generator tries to write code to serialize ReadOnlySequence<byte>, which is not possible.

API Proposal

// System.Text.Json source generator code
// ...

API Usage

public class Dto
{
    public ReadOnlySequence<byte> Data { get; set; }
}

[JsonSerializable(typeof(Dto))]
public partial class Class1JsonSerializationContext : JsonSerializerContext
{
}

Alternative Designs

No response

Risks

No response

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Issue Details

---

Background and motivation

In .NET 8.0, System.Text.Json source generator generates code to JSON serialize ReadOnlyMemory<byte> values the same way as byte[].

To avoid extra allocations, it would be nice to be able to JSON serialize ReadOnlySequence<byte> the same way.

Currently, the generator tries to write code to serialize ReadOnlySequence<byte>, which is not possible.

API Proposal

// System.Text.Json source generator code
// ...

API Usage

public class Dto
{
    public ReadOnlySequence<byte> Data { get; set; }
}

[JsonSerializable(typeof(Dto))]
public partial class Class1JsonSerializationContext : JsonSerializerContext
{
}

Alternative Designs

No response

Risks

No response

Author:	paulomorgado
Assignees:	-
Labels:	api-suggestion, area-System.Text.Json
Milestone:	-

[eiriktsarpalis]

It's essentially a duplicate of #67337. Once we add support for writing partial string values it should be trivial to include streaming converters for string, ReadOnlyMemory<byte> or ReadOnlySequence<byte>.