@RequiresApi(api = Build.VERSION_CODES.LOLLIPOP)
  public float getLetterSpacing() {
    return mParams.paint.getLetterSpacing();
  }
Gets the text letter-space value, which determines the spacing between characters. The value
returned is in ems. Normally, this value is 0.0.

@return The text letter-space value in ems.
@see #setLetterSpacing(float)
library/src/main/java/com/facebook/fbui/textlayoutbuilder/TextLayoutBuilder.java