import java.io.IOException;
import java.io.Reader;
import java.util.Iterator;
import javax.annotation.CheckForNull;

/**
 * A {@link Reader} that concatenates multiple readers.
 *
 * @author Bin Zhu
 * @since 1.0
 */
@J2ktIncompatible
@GwtIncompatible
@ElementTypesAreNonnullByDefault
class MultiReader extends Reader {
  private final Iterator<? extends CharSource> it;
  @CheckForNull private Reader current;