public ModifyableTableDescriptor setValue(final Bytes key, final Bytes value) {
      if (value == null || value.getLength() == 0) {
        values.remove(key);
      } else {
        values.put(key, value);
      }
      return this;
    }
Setter for storing metadata as a (key, value) pair in {@link #values} map
@param key   The key.
@param value The value. If null, removes the setting.
hbase-client/src/main/java/org/apache/hadoop/hbase/client/TableDescriptorBuilder.java