code: func Verify(ctx *Context, hash, password, salt []byte) (bool, error) {
  	if ctx == nil {
  		return false, ErrContext
  	}
  	if len(hash) == 0 {
  		return false, ErrHash
  	}
  
  	hash2, err := ctx.hash(password, salt)
  	if err != nil {
  		return false, err
  	}
  
  	return subtle.ConstantTimeCompare(hash, hash2) == 1, nil
  }
docs: // Verify verifies an Argon2 hash against a plaintext password.