BatchOperationUserdata

const BatchOperationUserdata = extern struct {
    batch: *Io.Batch,
    source: c.dispatch.source_t,
    operation: extern union {
        file_read_streaming: extern struct {
            data_ptr: [*]const []u8,
            data_len: usize,
        },
        file_write_streaming: extern struct {
            header_ptr: [*]const u8,
            header_len: usize,
            data_ptr: [*]const []const u8,
            data_len: usize,
            splat: usize,

            fn header(operation: *const @This()) []const u8 {
                return operation.header_ptr[0..operation.header_len];
            }

            fn data(operation: *const @This()) []const []const u8 {
                return operation.data_ptr[0..operation.data_len];
            }
        },
    },

    const Erased = Io.Operation.Storage.Pending.Userdata;

    comptime {
        assert(@sizeOf(BatchOperationUserdata) <= @sizeOf(Erased));
    }

    fn toErased(userdata: *BatchOperationUserdata) *Erased {
        return @ptrCast(userdata);
    }

    fn fromErased(erased: *Erased) *BatchOperationUserdata {
        return @ptrCast(erased);
    }
}