Importing Buffer Type

  class myClass {
    _encryptionKey: Buffer; // Errors: Cannot find name 'Buffer'.deno-ts(2580)
    _signatureKey: Buffer; // Errors: Cannot find name 'Buffer'.deno-ts(2580)
    constructor(secret: string, domain: string) {
      const keyMaterial = crypto.createHash("sha256").update(secret).digest();
      this._encryptionKey = keyMaterial.subarray(0, BLOCK_SIZE);
      this._signatureKey = keyMaterial.subarray(BLOCK_SIZE, 32);
    }
  }