[Tex/LaTex] How to fill the space between two \draw lines

Question

I am drawing two lines and I need to fill the space between them with a green color. How can I do that in tikz?

\documentclass{standalone}
\usepackage{pgfplots}
\usetikzlibrary{patterns}

\begin{document}
    \begin{tikzpicture}
            \draw (3.1,4.2) -- (2.45,3.8)  (3.1,4.1) -- (2.45,3.7);
    \end{tikzpicture}

\end{document}

I know one way is to draw a green thick line between these two. But I don't want to do that, as it is difficult to align these lines:

            \draw (3.1,4.2) -- (2.45,3.8)  (3.1,4.12) -- (2.45,3.72);
            \draw[line width=0.55mm, green] (3.1,4.16) -- (2.45,3.76);

Answer 1

using double :

\documentclass{standalone}
\usepackage{pgfplots}
\usetikzlibrary{patterns}

\begin{document}
\begin{tikzpicture}
  \draw[double=green] (3.1,4.2) -- (2.45,3.8);
\end{tikzpicture}
\begin{tikzpicture}
  \draw[double=green, double distance=.1cm] (3.1,4.2) -- (2.45,3.8);
\end{tikzpicture}
\begin{tikzpicture}
  \draw[double=green, double distance=.2cm] (3.1,4.2) -- (2.45,3.8);
\end{tikzpicture}
\end{document}