【报Bug】downloadFile header参数不生效

操作步骤：

uni.downloadFile({
url: 'http://192.168.1.2/xx.mp4',
header: {
a: 'b'
}
})
如上代码，用两个不同的版本，发送的HTTP请求不一致，
3.3.13为

array(8) {  
  ["icy-metadata"] => string(1) "1"  
  ["host"] => string(12) "192.168.1.2"  
  ["connection"] => string(5) "close"  
  ["range"] => string(8) "bytes="  
  ["accept"] => string(3) "*/*"  
  ["user-agent"] => string(224) "Mozilla/5.0 (Linux; Android 11; Redmi K20 Pro Premium Edition Build/RKQ1.200826.002; wv) AppleWebKit/537.36 (KHTML, like Gecko) Version/4.0 Chrome/98.0.4758.101 Mobile Safari/537.36 uni-app Html5Plus/1.0 (Immersed/34.909092)"  
  ["content-length"] => string(0) ""  
  ["content-type"] => string(0) ""  
}

3.2.16为

array(7) {  
  ["accept-encoding"] => string(4) "gzip"  
  ["connection"] => string(10) "Keep-Alive"  
  ["host"] => string(12) "192.168.1.2"  
  ["user-agent"] => string(154) "Mozilla/5.0 (Linux; Android 7.1.2; SM-G977N Build/LMY48Z; wv) AppleWebKit/537.36 (KHTML, like Gecko) Version/4.0 Chrome/92.0.4515.131 Mobile Safari/537.36"  
  ["a"] => string(1) "b"  
  ["content-length"] => string(0) ""  
  ["content-type"] => string(0) ""  
}

预期结果：

header携带参数

实际结果：

3.3.13未携带，3.2.16携带了