default void modifyNamespace(NamespaceDescriptor descriptor) throws IOException {
    get(modifyNamespaceAsync(descriptor), getSyncWaitTimeout(), TimeUnit.MILLISECONDS);
  }
Modify an existing namespace. Blocks until namespace has been successfully modified or an
exception is thrown.
@param descriptor descriptor which describes the new namespace
@throws IOException if a remote or network exception occurs
hbase-client/src/main/java/org/apache/hadoop/hbase/client/Admin.java