public Varnode createVarnode(BigInteger bigVal, BigInteger spaceVal, int size) {
		if (size > 8) {
			return null; // varnodes only suport long offsets.
		}
		// no space, assume a constant
		if (spaceVal == null) {
			return createConstantVarnode(bigVal.longValue(), size);
		}

		// spaceID is only an int.  If we have a bigger value, then bad space...
		long spaceID = spaceVal.longValue();
		int intSpaceID = (int) spaceID;
		if (intSpaceID != spaceID) {
			return null;
		}
		return createVarnode(bigVal.longValue(), spaceVal.intValue(), size);

	}
Check if the symbol at the address is read_only.

@param addr - address of the symbol

@return true if the block is read_only, and there are no write references.
Ghidra/Features/Base/src/main/java/ghidra/program/util/VarnodeContext.java