code: public ServiceFuture<KeyBundle> getKeyAsync(String vaultBaseUrl, String keyName,
              final ServiceCallback<KeyBundle> serviceCallback) {
          return getKeyAsync(vaultBaseUrl, keyName, "", serviceCallback);
      }
docs: Gets the public part of a stored key. The get key operation is applicable to
  all key types. If the requested key is symmetric, then no key material is
  released in the response. Authorization: Requires the keys/get permission.
  
  @param vaultBaseUrl
  The vault name, e.g. https://myvault.vault.azure.net
  @param keyName
  The name of the key
  @param serviceCallback
  the async ServiceCallback to handle successful and failed
  responses.
  @return the {@link ServiceFuture} object