"Ref Returns"

int _viewMatricesStartIndex;
int _projectionMatricesStartIndex;
int _worldMatricesStartIndex;
Matrix4x4[] _matrices;

public ref Matrix4x4 GetMatrix(MatrixType type, int offset) {
	switch (type) {
		case MatrixType.ViewMatrix:
			return ref _matrices[_viewMatricesStartIndex + offset];
		case MatrixType.ProjectionMatrix:
			return ref _matrices[_projectionMatricesStartIndex + offset];
		case MatrixType.WorldMatrix:
			return ref _matrices[_worldMatricesStartIndex + offset];
		default: 
			throw new ArgumentOutOfRangeException(nameof(type));
	}
}


Code snippet taken from "Two Decades of C#: A Reference - C# 7".