* An [MappedRange.InlineDelta] must be a mapping from a single code-point to a single code-point with a difference
 * that can be represented in 2^18-1.
 */
internal fun inlineDeltaOrNull(mapping: Mapping): MappedRange.InlineDelta? {
  if (mapping.hasSingleSourceCodePoint) {
    val sourceCodePoint = mapping.sourceCodePoint0
    val mappedCodePoints =
      mapping.mappedTo
        .utf8()