const HTTPCachePolicy({bool preventIntermediateProxyCaching: false, bool preventCaching: false, bool requireConditionalRequest: false, Duration expirationFromNow: null })

Creates a new cache policy.

Policies applied to Response.cachePolicy will add the appropriate headers to that response. See properties for definitions of arguments to this constructor.

Source 

const HTTPCachePolicy(
    {this.preventIntermediateProxyCaching: false,
      this.preventCaching: false, this.requireConditionalRequest: false,
      this.expirationFromNow: null});