segment
constructor(x: Number? = null, y: Number? = null, xend: Number? = null, yend: Number? = null, alpha: Number? = null, color: Any? = null, linetype: Any? = null, size: Number? = null, sizeStart: Number? = null, sizeEnd: Number? = null, strokeStart: Number? = null, strokeEnd: Number? = null, colorBy: String? = null, mapping: SegmentMapping.() -> Unit = {})