Hello, In [`prev_boundary`](https://github.com/unicode-rs/unicode-segmentation/blob/3ff9de65671d35753f5ad273b6bb4da028f5ebb4/src/grapheme.rs#L705) we have this check (for the following unwrap not to panic): ```rust if self.offset == chunk_start { return Err(GraphemeIncomplete::PrevChunk); } ``` I suggest this in [`next_boundary()`](https://github.com/unicode-rs/unicode-segmentation/blob/3ff9de65671d35753f5ad273b6bb4da028f5ebb4/src/grapheme.rs#L626) (for the same reason): ```rust if self.offset == chunk_start + chunk.len() { return Err(GraphemeIncomplete::NextChunk); } ``` Thank you!