WriteStringAttr
error = WriteStringAttr(file, "BEOS:TYPE", type);
error = WriteStringAttr(file, "BEOS:APP_SIG", signature);
error = WriteStringAttr(file, "BEOS:SNIFF_RULE", snifferRule);
CHK(WriteStringAttr(node, "BEOS:TYPE", "application/x-person") == B_OK);