@param map the map to encode
@param charset the charset to use for encoding (uses default encoding if null)
@param equalsForNullValue if True, then an '=' is always used, even
for parameters without a value. e.g. <code>"blah?a=&b=&c="</code>.
@return the MultiMap as a string encoded with % encodings.
Encode MultiMap with % encoding.
@param map the map to encode @param charset the charset to use for encoding (uses default encoding if null) @param equalsForNullValue if True, then an '=' is always used, even for parameters without a value. e.g. <code>"blah?a=&b=&c="</code>. @return the MultiMap as a string encoded with % encodings.