stream-csharp.cs

public void Main()
{
	//Stream class: http://msdn.microsoft.com/en-us/library/system.io.stream(v=vs.110).aspx
	using (FileStream config = File.Open("some.config", FileMode.Open))
	using (FileStream otherConfig = File.Open("other.config", FileMode.Open))
	{
		CallLibrary(config, otherConfig);
	}
}

public void CallLibrary(Stream config, Stream otherConfig)
{
	//Stream reader: http://msdn.microsoft.com/en-us/library/system.io.streamreader(v=vs.110).aspx
	using (StreamReader configReader = new StreamReader(config)) 
	using (StreamReader otherConfigReader = new StreamReader(otherConfig)) 
	{
		var configContent = configReader.ReadToEnd();
		var otherConfigContent = otherConfigReader.ReadToEnd();
	}
}