code: func (c *Client) DebugLevel(levelSpec string) (string, error) {
  	return c.DebugLevelAsync(levelSpec).Receive()
  }
docs: // DebugLevel dynamically sets the debug logging level to the passed level
  // specification.
  //
  // The levelspec can be either a debug level or of the form:
  // 	<subsystem>=<level>,<subsystem2>=<level2>,...
  //
  // Additionally, the special keyword 'show' can be used to get a list of the
  // available subsystems.
  //
  // NOTE: This is a btcd extension.