public static boolean isSet(Bundle bundle, String headerName) {
        return Boolean.valueOf(String.valueOf(bundle.getHeaders().get(headerName)));
    }
Returns true if the named header is present in the manifest of the given bundle.

@param bundle     The bundle whose manifest to check.
@param headerName The name of the header to check for.
@return True if header is present.
jdisc_core/src/main/java/com/yahoo/jdisc/application/OsgiHeader.java