my %params;
  if ( $params{content} ) { $request{content} = $params{content} }

  if ( $params{username} )   { $request{username}   = $params{username} }
  if ( $params{avatar_url} ) { $request{avatar_url} = $params{avatar_url} }
  if ( $params{tts} )        { $request{tts}        = JSON::PP::true }