public TextLayoutBuilder setTextSpacingMultiplier(float spacingMultiplier) {
    if (mParams.lineHeight == DEFAULT_LINE_HEIGHT && mParams.spacingMult != spacingMultiplier) {
      mParams.spacingMult = spacingMultiplier;
      mSavedLayout = null;
    }
    return this;
  }
Sets the line spacing multiplier for the layout. Line spacing multiplier will be ignored if
{@link TextLayoutBuilder#setLineHeight(float)} was used to set an explicit line height.

@param spacingMultiplier the value by which each line's height is multiplied
@return This {@link TextLayoutBuilder} instance
library/src/main/java/com/facebook/fbui/textlayoutbuilder/TextLayoutBuilder.java