create

        fn create(
            client: *Client,
            remote_host: HostName,
            port: u16,
            stream: Io.net.Stream,
        ) !*Tls {
            const io = client.io;
            const gpa = client.allocator;
            const alloc_len = allocLen(client, remote_host.bytes.len);
            const base = try gpa.alignedAlloc(u8, .of(Tls), alloc_len);
            errdefer gpa.free(base);
            const host_buffer = base[@sizeOf(Tls)..][0..remote_host.bytes.len];
            // The TLS client wants enough buffer for the max encrypted frame
            // size, and the HTTP body reader wants enough buffer for the
            // entire HTTP header. This means we need a combined upper bound.
            const tls_read_buffer_len = client.tls_buffer_size + client.read_buffer_size;
            const tls_read_buffer = host_buffer.ptr[host_buffer.len..][0..tls_read_buffer_len];
            const tls_write_buffer = tls_read_buffer.ptr[tls_read_buffer.len..][0..client.tls_buffer_size];
            const socket_write_buffer = tls_write_buffer.ptr[tls_write_buffer.len..][0..client.write_buffer_size];
            const socket_read_buffer = socket_write_buffer.ptr[socket_write_buffer.len..][0..client.tls_buffer_size];
            assert(base.ptr + alloc_len == socket_read_buffer.ptr + socket_read_buffer.len);
            @memcpy(host_buffer, remote_host.bytes);
            const tls: *Tls = @ptrCast(base);
            var random_buffer: [std.crypto.tls.Client.Options.entropy_len]u8 = undefined;
            io.random(&random_buffer);
            tls.* = .{
                .connection = .{
                    .client = client,
                    .stream_writer = stream.writer(io, tls_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 = .tls,
                },
                // TODO data race here on ca_bundle if the user sets `now` to null
                .client = std.crypto.tls.Client.init(
                    &tls.connection.stream_reader.interface,
                    &tls.connection.stream_writer.interface,
                    .{
                        .host = .{ .explicit = remote_host.bytes },
                        .ca = .{ .bundle = .{
                            .gpa = client.allocator,
                            .io = client.io,
                            .lock = &client.ca_bundle_lock,
                            .bundle = &client.ca_bundle,
                        } },
                        .ssl_key_log = client.ssl_key_log,
                        .read_buffer = tls_read_buffer,
                        .write_buffer = socket_write_buffer,
                        .entropy = &random_buffer,
                        .realtime_now = client.now.?,
                        // This is appropriate for HTTPS because the HTTP headers contain
                        // the content length which is used to detect truncation attacks.
                        .allow_truncation_attacks = true,
                    },
                ) catch |err| switch (err) {
                    error.WriteFailed => return tls.connection.stream_writer.err.?,
                    error.ReadFailed => return tls.connection.stream_reader.err.?,
                    else => |e| return e,
                },
            };
            return tls;
        }