How to use the @now/build-utils.FileFsRef.fromFsPath function in @now/build-utils

async handleFileModified(
    fsPath: string,
    changed: Set,
    removed: Set
  ): Promise {
    const name = relative(this.cwd, fsPath);
    try {
      this.files[name] = await FileFsRef.fromFsPath({ fsPath });
      fileChanged(name, changed, removed);
      this.output.debug(`File modified: ${name}`);
    } catch (err) {
      if (err.code === 'ENOENT') {
        this.output.debug(`File modified, but has since been deleted: ${name}`);
        fileRemoved(name, this.files, changed, removed);
      } else {
        throw err;
      }
    }
  }

async handleFileCreated(
    fsPath: string,
    changed: Set,
    removed: Set
  ): Promise {
    const name = relative(this.cwd, fsPath);
    try {
      this.files[name] = await FileFsRef.fromFsPath({ fsPath });
      fileChanged(name, changed, removed);
      this.output.debug(`File created: ${name}`);
    } catch (err) {
      if (err.code === 'ENOENT') {
        this.output.debug(`File created, but has since been deleted: ${name}`);
        fileRemoved(name, this.files, changed, removed);
      } else {
        throw err;
      }
    }
  }

async handleFileModified(
    fsPath: string,
    changed: Set,
    removed: Set
  ): Promise {
    const name = relative(this.cwd, fsPath);
    try {
      this.files[name] = await FileFsRef.fromFsPath({ fsPath });
      fileChanged(name, changed, removed);
      this.output.debug(`File modified: ${name}`);
    } catch (err) {
      if (err.code === 'ENOENT') {
        this.output.debug(`File modified, but has since been deleted: ${name}`);
        fileRemoved(name, this.files, changed, removed);
      } else {
        throw err;
      }
    }
  }

async handleFileCreated(
    fsPath: string,
    changed: Set,
    removed: Set
  ): Promise {
    const name = relative(this.cwd, fsPath);
    try {
      this.files[name] = await FileFsRef.fromFsPath({ fsPath });
      fileChanged(name, changed, removed);
      this.output.debug(`File created: ${name}`);
    } catch (err) {
      if (err.code === 'ENOENT') {
        this.output.debug(`File created, but has since been deleted: ${name}`);
        fileRemoved(name, this.files, changed, removed);
      } else {
        throw err;
      }
    }
  }

async handleFileModified(
    fsPath: string,
    changed: Set,
    removed: Set
  ): Promise {
    const name = relative(this.cwd, fsPath);
    try {
      this.files[name] = await FileFsRef.fromFsPath({ fsPath });
      fileChanged(name, changed, removed);
      this.output.debug(`File modified: ${name}`);
    } catch (err) {
      if (err.code === 'ENOENT') {
        this.output.debug(`File modified, but has since been deleted: ${name}`);
        fileRemoved(name, this.files, changed, removed);
      } else {
        throw err;
      }
    }
  }