public Map<String, List<String>> getHeaders() {
        return headers;
    }
Returns an unmodifiable Map of all values of all HTTP headers on the
request, where each Map key is a header name. Each Map value is an
unmodifiable List of all values provided for the associated header and
will contain at least one value. Header names are case-insensitive, and
the returned map will perform lookups in a case-insensitive manner.

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