public Set<String> getHeaderNames() {
        return headers.keySet();
    }
Returns an unmodifiable Set of the names of all HTTP headers present on
the request. If there are no headers, this set will be empty. Header
names are case-insensitive, and the returned Set will perform lookups in
a case-insensitive manner.

@return
    An unmodifiable Set of the names of all HTTP headers present on the
    request.
guacamole-ext/src/main/java/org/apache/guacamole/net/RequestDetails.java