code: public PagedList<KeyItem> getKeys(final String vaultBaseUrl) {
          ServiceResponse<Page<KeyItem>> response = getKeysSinglePageAsync(vaultBaseUrl).toBlocking().single();
          return new PagedList<KeyItem>(response.body()) {
              @Override
              public Page<KeyItem> nextPage(String nextPageLink) {
                  return getKeysNextSinglePageAsync(nextPageLink).toBlocking().single().body();
              }
          };
      }
docs: List keys in the specified vault.
  Retrieves a list of the keys in the Key Vault as JSON Web Key structures that contain the public part of a stored key. The LIST operation is applicable to all key types, however only the base key identifier, attributes, and tags are provided in the response. Individual versions of a key are not listed in the response. This operation requires the keys/list permission.
  
  @param vaultBaseUrl The vault name, for example https://myvault.vault.azure.net.
  @throws IllegalArgumentException thrown if parameters fail the validation
  @throws KeyVaultErrorException thrown if the request is rejected by server
  @throws RuntimeException all other wrapped checked exceptions if the request fails to be sent
  @return the PagedList&lt;KeyItem&gt; object if successful.