create

        fn create(
            client: *Client,
            remote_host: HostName,
            port: u16,
            stream: Io.net.Stream,
        ) error{OutOfMemory}!*Plain {
            const io = client.io;
            const gpa = client.allocator;
            const alloc_len = allocLen(client, remote_host.bytes.len);
            const base = try gpa.alignedAlloc(u8, .of(Plain), alloc_len);
            errdefer gpa.free(base);
            const host_buffer = base[@sizeOf(Plain)..][0..remote_host.bytes.len];
            const socket_read_buffer = host_buffer.ptr[host_buffer.len..][0..client.read_buffer_size];
            const socket_write_buffer = socket_read_buffer.ptr[socket_read_buffer.len..][0..client.write_buffer_size];
            assert(base.ptr + alloc_len == socket_write_buffer.ptr + socket_write_buffer.len);
            @memcpy(host_buffer, remote_host.bytes);
            const plain: *Plain = @ptrCast(base);
            plain.* = .{
                .connection = .{
                    .client = client,
                    .stream_writer = stream.writer(io, socket_write_buffer),
                    .stream_reader = stream.reader(io, socket_read_buffer),
                    .pool_node = .{},
                    .port = port,
                    .host_len = @intCast(remote_host.bytes.len),
                    .proxied = false,
                    .closing = false,
                    .protocol = .plain,
                },
            };
            return plain;
        }