public void getContactById(final String contactId, final Promise promise) {
        getExecutor().execute(() -> {
            Context context = getReactApplicationContext();
            ContentResolver cr = context.getContentResolver();
            ContactsProvider contactsProvider = new ContactsProvider(cr);
            WritableMap contact = contactsProvider.getContactById(contactId);
            promise.resolve(contact);
        });
    }
Retrieves <code>contact</code> for contact, or <code>null</code> if not
available.

@param contactId contact identifier, <code>recordID</code>
android/src/main/java/com/rt2zz/reactnativecontacts/impl/ContactsManagerImpl.java