in core/src/main/scala/com/spotify/featran/FeatureBuilder.scala [230:247]
override def add(name: String, value: Double): Unit = {
indices(i) = offset
values(i) = FloatingPoint[T].fromDouble(value)
if (withNames) {
namesBuilder += name
}
i += 1
offset += 1
if (indices.length == i) {
val n = indices.length * 2
val newIndices = new Array[Int](n)
val newValues = new Array[T](n)
Array.copy(indices, 0, newIndices, 0, indices.length)
Array.copy(values, 0, newValues, 0, indices.length)
indices = newIndices
values = newValues
}
}