使用PHP的Curl API请求 - 长pretransfer_time

Question

当我用php发出curl api请求时，但响应返回超时。我试图运行curl_getinfo（$ ch）。发现pretransfer_time花费了近2个。请告诉我原因，谢谢。

{
"error": "Operation timed out after 2000 milliseconds with 0 out of -1 bytes received",
"info": {
    "url": "https://card.com/v1/giftcard/code",
    "content_type": null,
    "http_code": 0,
    "header_size": 0,
    "request_size": 329,
    "filetime": -1,
    "ssl_verify_result": 0,
    "redirect_count": 0,
    "total_time": 1.99945,
    "namelookup_time": 0.012225,
    "connect_time": 0.012532,
    "pretransfer_time": 1.967348,
    "size_upload": 185,
    "size_download": 0,
    "speed_download": 0,
    "speed_upload": 92,
    "download_content_length": -1,
    "upload_content_length": 185,
    "starttransfer_time": 0,
    "redirect_time": 0,
    "redirect_url": "",
    "primary_ip": "120.55.16.0",
    "certinfo": [],
    "primary_port": 443,
    "local_ip": "101.37.205.65",
    "local_port": 57156
}}