public boolean isNullEntry() {
		return characteristics == 0 && timeDateStamp == 0 && forwarderChain == 0 && name == 0 &&
			firstThunk == 0;
	}
Checks to see if this descriptor is a null entry.  A null entry
indicates that no more descriptors follow in the import table.

@return True if this descriptor is a null entry; otherwise, false.
Ghidra/Features/Base/src/main/java/ghidra/app/util/bin/format/pe/ImportDescriptor.java