func (r *Request) SetFile(param, filePath string) *Request {
	r.isMultiPart = true
	r.FormData.Set("@"+param, filePath)
	return r
}
SetFile method is to set single file field name and its path for multipart upload.
resty.R().
SetFile("my_file", "/Users/jeeva/Gas Bill - Sep.pdf")
package resty
import (
	"encoding/base64"
	"encoding/json"
	"encoding/xml"
	"fmt"
	"io"
	"net"
	"net/url"
	"reflect"
	"strings"
)
type SRVRecord struct {
	Service string
	Domain  string
}
func (r *Request) SetHeader(header, value string) *Request {
	r.Header.Set(header, value)
	return r
}
func (r *Request) SetHeaders(headers map[string]string) *Request {
	for h, v := range headers {
		r.SetHeader(h, v)
	}
	return r
}
func (r *Request) SetQueryParam(param, value string) *Request {
	r.QueryParam.Set(param, value)
	return r
}
func (r *Request) SetQueryParams(params map[string]string) *Request {
	for p, v := range params {
		r.SetQueryParam(p, v)
	}
	return r
}
func (r *Request) SetMultiValueQueryParams(params url.Values) *Request {
	for p, v := range params {
		for _, pv := range v {
			r.QueryParam.Add(p, pv)
		}
	}
	return r
}
func (r *Request) SetQueryString(query string) *Request {
	params, err := url.ParseQuery(strings.TrimSpace(query))
	if err == nil {
		for p, v := range params {
			for _, pv := range v {
				r.QueryParam.Add(p, pv)
			}
		}
	} else {
		r.client.Log.Printf("ERROR %v", err)
	}
	return r
}
func (r *Request) SetFormData(data map[string]string) *Request {
	for k, v := range data {
		r.FormData.Set(k, v)
	}
	return r
}
func (r *Request) SetMultiValueFormData(params url.Values) *Request {
	for k, v := range params {
		for _, kv := range v {
			r.FormData.Add(k, kv)
		}
	}
	return r
}
func (r *Request) SetBody(body interface{}) *Request {
	r.Body = body
	return r
}
func (r *Request) SetResult(res interface{}) *Request {
	r.Result = getPointer(res)
	return r
}
func (r *Request) SetError(err interface{}) *Request {
	r.Error = getPointer(err)
	return r
}