func (req *Request) MultipartForm() (*multipart.Form, error) {
	if req.multipartForm != nil {
		return req.multipartForm, nil
	}
	req.multipartFormBoundary = string(req.Header.MultipartFormBoundary())
	if len(req.multipartFormBoundary) == 0 {
		return nil, ErrNoMultipartForm
	}
	ce := req.Header.peek(strContentEncoding)
	body := req.body
	if bytes.Equal(ce, strGzip) {
		var err error
		if body, err = AppendGunzipBytes(nil, body); err != nil {
			return nil, fmt.Errorf("cannot gunzip request body: %s", err)
		}
	} else if len(ce) > 0 {
		return nil, fmt.Errorf("unsupported Content-Encoding: %q", ce)
	}
	f, err := readMultipartForm(bytes.NewReader(body), req.multipartFormBoundary, len(body), len(body))
	if err != nil {
		return nil, err
	}
	req.multipartForm = f
	return f, nil
}
MultipartForm returns requests's multipart form.

Returns ErrNoMultipartForm if request's Content-Type
isn't 'multipart/form-data'.

RemoveMultipartFormFiles must be called after returned multipart form
is processed.
package fasthttp
import (
	"bufio"
	"bytes"
	"errors"
	"fmt"
	"io"
	"mime/multipart"
	"os"
	"sync"
)
type Request struct {
	noCopy noCopy
	Header RequestHeader
	body []byte
	w    requestBodyWriter
	bodyStream io.Reader
	uri      URI
	postArgs Args
	multipartForm         *multipart.Form
	multipartFormBoundary string
	parsedURI      bool
	parsedPostArgs bool
}
type Response struct {
	noCopy noCopy
	Header ResponseHeader
	body []byte
	w    responseBodyWriter
	bodyStream io.Reader
	SkipBody bool
}
func (req *Request) SetRequestURI(requestURI string) {
	req.Header.SetRequestURI(requestURI)
	req.parsedURI = false
}
func (req *Request) SetRequestURIBytes(requestURI []byte) {
	req.Header.SetRequestURIBytes(requestURI)
	req.parsedURI = false
}
func (req *Request) RequestURI() []byte {
	if req.parsedURI {
		requestURI := req.uri.RequestURI()
		req.SetRequestURIBytes(requestURI)
	}
	return req.Header.RequestURI()
}
func (resp *Response) StatusCode() int {
	return resp.Header.StatusCode()
}
func (resp *Response) SetStatusCode(statusCode int) {
	resp.Header.SetStatusCode(statusCode)
}
func (resp *Response) ConnectionClose() bool {
	return resp.Header.ConnectionClose()
}
func (resp *Response) SetConnectionClose() {
	resp.Header.SetConnectionClose()
}
func (req *Request) ConnectionClose() bool {
	return req.Header.ConnectionClose()
}
func (req *Request) SetConnectionClose() {
	req.Header.SetConnectionClose()
}
func (resp *Response) SendFile(path string) error {
	f, err := os.Open(path)
	if err != nil {
		return err
	}
	fileInfo, err := f.Stat()
	if err != nil {
		f.Close()
		return err
	}
	size64 := fileInfo.Size()
	size := int(size64)
	if int64(size) != size64 {
		size = -1
	}
	resp.Header.SetLastModified(fileInfo.ModTime())
	resp.SetBodyStream(f, size)
	return nil
}
func (req *Request) SetBodyStream(bodyStream io.Reader, bodySize int) {
	req.ResetBody()
	req.bodyStream = bodyStream
	req.Header.SetContentLength(bodySize)
}
func (resp *Response) SetBodyStream(bodyStream io.Reader, bodySize int) {
	resp.ResetBody()
	resp.bodyStream = bodyStream
	resp.Header.SetContentLength(bodySize)
}
func (req *Request) SetBodyStreamWriter(sw StreamWriter) {
	sr := NewStreamReader(sw)
	req.SetBodyStream(sr, -1)
}
func (resp *Response) SetBodyStreamWriter(sw StreamWriter) {
	sr := NewStreamReader(sw)
	resp.SetBodyStream(sr, -1)
}
func (resp *Response) BodyWriter() io.Writer {
	resp.w.r = resp
	return &resp.w
}
func (req *Request) BodyWriter() io.Writer {
	req.w.r = req
	return &req.w
}
type responseBodyWriter struct {
	r *Response
}
func (w *responseBodyWriter) Write(p []byte) (int, error) {
	w.r.AppendBody(p)
	return len(p), nil
}
type requestBodyWriter struct {
	r *Request
}
func (w *requestBodyWriter) Write(p []byte) (int, error) {
	w.r.AppendBody(p)
	return len(p), nil
}
func (resp *Response) Body() []byte {
	if resp.bodyStream != nil {
		var w ByteBuffer
		_, err := copyZeroAlloc(&w, resp.bodyStream)
		resp.closeBodyStream()
		if err != nil {
			resp.body = append(resp.body[:0], err.Error()...)
		} else {
			resp.body = append(resp.body[:0], w.B...)
		}
	}
	return resp.body
}
func (req *Request) BodyGunzip() ([]byte, error) {
	return gunzipData(req.Body())
}
func (resp *Response) BodyGunzip() ([]byte, error) {
	return gunzipData(resp.Body())
}
func gunzipData(p []byte) ([]byte, error) {
	var bb ByteBuffer
	_, err := WriteGunzip(&bb, p)
	if err != nil {
		return nil, err
	}
	return bb.B, nil
}
func (req *Request) BodyInflate() ([]byte, error) {
	return inflateData(req.Body())
}
func (resp *Response) BodyInflate() ([]byte, error) {
	return inflateData(resp.Body())
}
func inflateData(p []byte) ([]byte, error) {
	var bb ByteBuffer
	_, err := WriteInflate(&bb, p)
	if err != nil {
		return nil, err
	}
	return bb.B, nil
}
func (req *Request) BodyWriteTo(w io.Writer) error {
	if req.bodyStream != nil {
		_, err := copyZeroAlloc(w, req.bodyStream)
		req.closeBodyStream()
		return err
	}
	if req.onlyMultipartForm() {
		return WriteMultipartForm(w, req.multipartForm, req.multipartFormBoundary)
	}
	_, err := w.Write(req.body)
	return err
}
func (resp *Response) BodyWriteTo(w io.Writer) error {
	if resp.bodyStream != nil {
		_, err := copyZeroAlloc(w, resp.bodyStream)
		resp.closeBodyStream()
		return err
	}
	_, err := w.Write(resp.body)
	return err
}
func (resp *Response) AppendBody(p []byte) {
	resp.closeBodyStream()
	resp.body = append(resp.body, p...)
}
func (resp *Response) AppendBodyString(s string) {
	resp.closeBodyStream()
	resp.body = append(resp.body, s...)
}
func (resp *Response) SetBody(body []byte) {
	resp.closeBodyStream()
	resp.body = append(resp.body[:0], body...)
}
func (resp *Response) SetBodyString(body string) {
	resp.closeBodyStream()
	resp.body = append(resp.body[:0], body...)
}
func (resp *Response) ResetBody() {
	resp.closeBodyStream()
	resp.body = resp.body[:0]
}
func (req *Request) Body() []byte {
	if req.bodyStream != nil {
		var w ByteBuffer
		_, err := copyZeroAlloc(&w, req.bodyStream)
		req.closeBodyStream()
		if err != nil {
			req.body = append(req.body[:0], err.Error()...)
		} else {
			req.body = append(req.body[:0], w.B...)
		}
	} else if req.onlyMultipartForm() {
		body, err := marshalMultipartForm(req.multipartForm, req.multipartFormBoundary)
		if err != nil {
			return []byte(err.Error())
		}
		return body
	}
	return req.body
}
func (req *Request) AppendBody(p []byte) {
	req.RemoveMultipartFormFiles()
	req.closeBodyStream()
	req.body = append(req.body, p...)
}
func (req *Request) AppendBodyString(s string) {
	req.RemoveMultipartFormFiles()
	req.closeBodyStream()
	req.body = append(req.body, s...)
}
func (req *Request) SetBody(body []byte) {
	req.RemoveMultipartFormFiles()
	req.closeBodyStream()
	req.body = append(req.body[:0], body...)
}
func (req *Request) SetBodyString(body string) {
	req.RemoveMultipartFormFiles()
	req.closeBodyStream()
	req.body = append(req.body[:0], body...)
}
func (req *Request) ResetBody() {
	req.RemoveMultipartFormFiles()
	req.closeBodyStream()
	req.body = req.body[:0]
}
func (req *Request) CopyTo(dst *Request) {
	req.copyToSkipBody(dst)
	dst.body = append(dst.body[:0], req.body...)
}
func (req *Request) copyToSkipBody(dst *Request) {
	dst.Reset()
	req.Header.CopyTo(&dst.Header)
	req.uri.CopyTo(&dst.uri)
	dst.parsedURI = req.parsedURI
	req.postArgs.CopyTo(&dst.postArgs)
	dst.parsedPostArgs = req.parsedPostArgs
}
func (resp *Response) CopyTo(dst *Response) {
	resp.copyToSkipBody(dst)
	dst.body = append(dst.body[:0], resp.body...)
}
func (resp *Response) copyToSkipBody(dst *Response) {
	dst.Reset()
	resp.Header.CopyTo(&dst.Header)
	dst.SkipBody = resp.SkipBody
}
func swapRequestBody(a, b *Request) {
	a.body, b.body = b.body, a.body
	a.bodyStream, b.bodyStream = b.bodyStream, a.bodyStream
}
func swapResponseBody(a, b *Response) {
	a.body, b.body = b.body, a.body
	a.bodyStream, b.bodyStream = b.bodyStream, a.bodyStream
}
func (req *Request) URI() *URI {
	req.parseURI()
	return &req.uri
}
func (req *Request) parseURI() {
	if req.parsedURI {
		return
	}
	req.parsedURI = true
	req.uri.parseQuick(req.Header.RequestURI(), &req.Header)
}
func (req *Request) PostArgs() *Args {
	req.parsePostArgs()
	return &req.postArgs
}
func (req *Request) parsePostArgs() {
	if req.parsedPostArgs {
		return
	}
	req.parsedPostArgs = true
	if !bytes.Equal(req.Header.ContentType(), strPostArgsContentType) {
		return
	}
	req.postArgs.ParseBytes(req.body)
	return
}
var ErrNoMultipartForm = errors.New("request has no multipart/form-data Content-Type")