in library/src/main/java/com/facebook/fbui/textlayoutbuilder/TextLayoutBuilder.java [367:373]
public TextLayoutBuilder setTextSpacingExtra(float spacingExtra) {
if (mParams.lineHeight == DEFAULT_LINE_HEIGHT && mParams.spacingAdd != spacingExtra) {
mParams.spacingAdd = spacingExtra;
mSavedLayout = null;
}
return this;
}