Finds the element whose ID is id.
public PdfStructureElement? FindElementById(ReadOnlySpan<byte> id)
The identifier's bytes (IDs are byte strings, compared byte for byte).
null.ISO 32000-2 Table 354 (IDTree) and Table 355 (ID): looked up in the ID tree; when the tree is missing, does not
list the ID, or names an element whose ID differs, the elements reachable through K are searched instead.