# DownloadTask.onHeadersReceived(function callback)

Start from base library version 2.1.0. Please remaining backward compatible.

with Promise style call: Not supported

Mini Program plugin: Support

to monitor HTTP Response Header Events. Will be earlier than the request to complete the event

# parameter

# function callback

HTTP Response Header Event callback function

# parameter

# Object res
attribute type Introductions
header Object Returned by the developer server HTTP Response Header