The charset of this part's content. Each part of MultiPart body can has it's own charset set.
Default not set.

@param charset the charset
@return self
172655
public Part<T> charset(Charset charset) {
        requireNonNull(charset);
        return new Part<>(name, fileName, body, contentType, charset, partWriter);
    }
605153
public static String decode(String content, Charset charset) {
		if (null == charset) {
			charset = CharsetUtil.defaultCharset();
		}
		return decode(content, charset.name());
	}
1223284
public Charset getCharsetParameter() {
    String value = getParameter("charset");
    return value == null ? null : Charset.forName(value);
  }
535870
public function charset($charset = null)
    {
        if (!func_num_args()) {
            return $this->_charset;
        }
        $this->_charset = $charset ? strtoupper($charset) : null;
        return $this;
    }
559835
public function setCharset($charset)
    {
        $prev = $this->charset;

        $charset = strtoupper($charset);
        $charset = null === $charset || 'UTF-8' === $charset || 'UTF8' === $charset ? 'CP1252' : $charset;

        $this->charset = $charset;

        return $prev;
    }
733083
public function charset($charset = null)
    {
        deprecationWarning(
            'Response::charset() is deprecated. ' .
            'Use getCharset()/withCharset() instead.'
        );

        if ($charset === null) {
            return $this->_charset;
        }
        $this->_charset = $charset;
        $this->_setContentType();

        return $this->_charset;
    }
662489
private static Charset getCharset(MediaType mediaType)
	{
		String charsetName = mediaType.getParameters().get(MediaType.CHARSET_PARAMETER);
		Charset charset;
		
		if (charsetName != null)
		{
			charset = Charset.forName(charsetName);
		}
		else
		{
			charset = DEFAULT_CHARSET;
		}
		
		return charset;
	}
1106093
public Charset getContentCharset() {
    return mediaType == null || mediaType.getCharsetParameter() == null
        ? Charsets.ISO_8859_1
        : mediaType.getCharsetParameter();
  }
1178498
public function setBody($body, $contentType = null, $charset = null)
    {
        if (isset($charset)) {
            $this->setCharset($charset);
        }
        $body = $this->convertString($body);

        parent::setBody($body, $contentType);

        return $this;
    }
255105
public function setCharset($charset)
    {
        $this->charset = $charset;
        if (!$this->headerCharset) {
            $this->headerCharset = $charset;
        }

        return $this;
    }
619350
public function setCharacterSet($charset)
    {
        $this->charset = $charset;
        $this->charReader = null;
        $this->mapType = 0;
    }
73846
public Charset getCharSet() {
		String charSet = getParameter(PARAM_CHARSET);
		return (charSet != null ? Charset.forName(unquote(charSet)) : null);
	}
927459
public String readString(final String charset) throws IOException {
        byte ch;
        int cnt = 0;
        final byte [] byteArrBuff = new byte[byteBuffer.remaining()];
        while (byteBuffer.remaining() > 0 && ((ch = byteBuffer.get()) != 0)) {
            byteArrBuff[cnt++] = ch;
        }
        return new String(byteArrBuff,0,cnt);
    }
1337134
def charset(self) -> Optional[str]:
        """"""
        raw = self._headers.get(hdrs.CONTENT_TYPE)  # type: ignore
        if self._stored_content_type != raw:
            self._parse_content_type(raw)
        return self._content_dict.get('charset')
691679
public Charset getCharset() {
        String charset = getParameter(PARAM_CHARSET);
        return (charset != null ? Charset.forName(unquote(charset)) : null);
    }
440509
private static Charset getCharset(HttpOutputMessage outputMessage)
	{
		Charset charset = outputMessage.getHeaders().getContentType().getCharSet();
		
		if (charset == null)
		{
			charset = DEFAULT_CHARSET;
		}
		
		return charset;
	}
178743
public MessageProtocol withCharset(String charset) {
        return new MessageProtocol(contentType, Optional.ofNullable(charset), version);
    }