• New directive 'H2MaxDataFrameLen n' to limit the maximum amount of response
  body bytes put into a single HTTP/2 DATA frame. Setting this to 0 places
  no limit (but the max size allowed by the protocol is observed).
  The module, by default, tries to use the maximum size possible, which is
  somewhat around 16KB.
  This sets the maximum. When less response data is availble, smaller frames
  will be sent.