@Override
    public int getHeaderPosition() {
        if (!section.hasHeader()) {
            throw new IllegalStateException("Section doesn't have a header");
        }

        return getSectionPosition();
    }
This class represents a {@link Section Section} in the {@link SectionedRecyclerViewAdapter SectionedRecyclerViewAdapter}.
<p>
It provides helper methods for:
<ul>
<li>identifying position of this {@link Section Section}'s items in the {@link SectionedRecyclerViewAdapter SectionedRecyclerViewAdapter}</li>
<li>identifying position of the {@link SectionedRecyclerViewAdapter SectionedRecyclerViewAdapter} in this {@link Section Section}</li>
<li>notifying {@link SectionedRecyclerViewAdapter SectionedRecyclerViewAdapter} of item changes in this Section</li>
</ul>
library/src/main/java/io/github/luizgrp/sectionedrecyclerviewadapter/SectionAdapter.java