GetShared returns the generated abundance `data.frame` from the `cluster()` function
Examples
cutoff <- 0.2
count_table <- read_count(example_path("amazon.full.count_table"))
distance_data <- read_dist(example_path("amazon_column.dist"),
count_table, cutoff, FALSE)
df_clusters <- cluster(distance_data, cutoff, method = "opticlust")
shared <- get_abundance(df_clusters)