draw_arrow example panics

[XBagon]

When moving the mouse over the exact center of an arrow, the example crashes due to a panic. crash.log

[mitchmindtree]

Thanks for this, it looks like the crux of the issue is here:

RUST_BACKTRACE=1 cargo run --release --example draw_arrow
    Finished release [optimized] target(s) in 0.36s
     Running `target\release\examples\draw_arrow.exe`
thread 'main' panicked at 'not implemented', nannou\src\draw\mesh\builder.rs:91:9

which is an unimplemented! panic in the GeometryBuilder::abort_geometry implementation. We might need to investigate exactly what conditions can cause a lyon geometry builder to abort and handle it accordingly here, whether that's ignoring it or clearing the mesh, etc.

[nidnogg]

Commenting out that unimplemented! panic, I'm getting a failed to tessellate path: UnsupportedParamater on my terminal, avoiding a full panic. Funnily enough though I can't find out where abort_geometry is being called.

Is that possibly called from inside a git submodule or a crate dependency?