private static int getStructLength(Structure struct) {
		return struct.isZeroLength() ? 0 : struct.getLength();
	}
Returns the value of this java field.

@param <R> type of the result value
@param structInstance object containing the field
@param expectedType expected class of the value 
@return value of the field, or null if the field's value is not of expected type
@throws IOException if error accessing java field
Ghidra/Features/Base/src/main/java/ghidra/app/util/bin/format/golang/structmapping/FieldOutputInfo.java