chore: add more comments

        this.#supportsAbbExec = adb.canUseFeature(AdbFeature.AbbExec);

    }

    /**

     * Spawn a new `cmd` command. It will use ADB's `abb` command if available.

     *

     * @param shellProtocol

     * Whether to use shell protocol. If `true`, `stdout` and `stderr` will be separated.

     *

     * `cmd` doesn't use PTY, so even when shell protocol is used,

     * resizing terminal size and closing `stdin` are not supported.

     * @param command The command to run.

     * @param args The arguments to pass to the command.

     * @returns An `AdbSubprocessProtocol` that provides output streams.

     */

    async spawn(

        shellProtocol: boolean,

        command: string,

            PACKAGE_MANAGER_INSTALL_OPTIONS_MAP,

        );

        if (!options?.skipExisting) {

            // Compatibility with old versions of pm

            // Today `pm` defaults to replace existing application (`-r` will be ignored),

            // but old versions defaults to skip existing application (like `-R`, but obviously

            // they didn't have this switch and ignores it if present).

            // If `skipExisting` is not set, add `-r` to ensure compatibility with old versions.

            args.push("-r");

        }

        return args;

            await sync.dispose();

        }

        // Starting from Android 7, `pm` is only a wrapper for `cmd package`,

        // and `cmd package` launches faster than `pm`.

        // But `cmd package` can't read `/data/local/tmp` folder due to SELinux policy,

        // so installing a file must use `pm`.

        // Starting from Android 7, `pm` becomes a wrapper to `cmd package`.

        // The benefit of `cmd package` is it starts faster than the old `pm`,

        // because it connects to the already running `system` process,

        // instead of initializing all system components from scratch.

        //

        // But launching `cmd package` directly causes it to not be able to

        // read files in `/data/local/tmp` (and many other places) due to SELinux policies,

        // so installing files must still use `pm`.

        // (the starting executable file decides which SELinux policies to apply)

        const args = this.#buildInstallArguments("install", options);

        args.push(filePath);

        options?: Partial<PackageManagerInstallOptions>,

    ): Promise<void> {

        // Android 7 added both `cmd` command and streaming install support,

        // we can't detect whether `pm` supports streaming install,

        // so we detect `cmd` command support instead.

        // It's hard to detect whether `pm` supports streaming install (unless actually trying),

        // so check for whether `cmd` is supported,

        // and assume `pm` streaming install support status is same as that.

        if (!this.#cmd.supportsCmd) {

            // Fall back to push file then install

            await this.pushAndInstallStream(stream, options);

            return;

        }

        const args = this.#buildInstallArguments("install", options);

        // Remove `pm` from args, final command will starts with `cmd package install`

        // Remove `pm` from args, `Cmd#spawn` will prepend `cmd <command>` so the final args

        // will be `cmd package install <args>`

        args.shift();

        args.push("-S", size.toString());

        const process = await this.#cmd.spawn(false, "package", ...args);

        let installer: string | undefined;

        let uid: number | undefined;

        // Parse backwards

        // The output format is easier to parse backwards

        let index = line.indexOf(" uid:");

        if (index !== -1) {

            uid = Number.parseInt(line.substring(index + " uid:".length), 10);

            line = line.substring(0, index);

        }

        // `sourceDir` may contain `=` so use `lastIndexOf`

        // `sourceDir` may contain `=` characters

        // (because in newer Android versions it's a base64 string of encrypted package name),

        // so use `lastIndexOf`

        index = line.lastIndexOf("=");

        if (index !== -1) {

            sourceDir = line.substring(0, index);

        const process = await this.#cmdOrSubprocess(args);

        const reader = process.stdout

            .pipeThrough(new TextDecoderStream())

            // FIXME: `SplitStringStream` will throw away some data

            // if it doesn't end with a separator. So each chunk of data

            // must contain several complete lines.

            .pipeThrough(new SplitStringStream("\n"))

            .getReader();

        while (true) {