// FIXME: plan
// * Generate a mapping from node ids to chunk ids
// * Do boundary nodes go to multiple chunks?
// * Process weakly connected components separately (in parallel?)
// * For each chunk in the component, create a subgraph and write it as GFA to a file
// * For each path in the component, trace it and write the corresponding fragments to the chunk GFA files
// * Do a single pass over the GAF file and partition the alignments between chunks
// * Trace each alignment and clip it into pieces corresponding to the chunks
// * Write the clipped pieces to the appropriate chunk GAF files