<PackageReference Include="NETStandard.Library" Version="2.0.0-preview1-25301-01" />
System.Collections.Specialized.StringDictionary
public virtual int Count {
get; }
public virtual string this[
string key] {
get;
set; }
public virtual void Add(
string key,
string value)
public virtual void Clear()
public virtual void Remove(
string key)