public KeyStoreCredentialResolverBuilder keyPassword(String name, String password) {
        requireNonNull(name, "name");
        requireNonNull(password, "password");
        checkArgument(!keyPasswords.containsKey(name), "key already exists: %s", name);
        keyPasswords.put(name, password);
        return this;
    }
Adds a key name and its password to the {@link KeyStoreCredentialResolverBuilder}.
saml/src/main/java/com/linecorp/armeria/server/saml/KeyStoreCredentialResolverBuilder.java