diff --git a/R/bitset.R b/R/bitset.R
index e600680..8a2d623 100644
--- a/R/bitset.R
+++ b/R/bitset.R
@@ -5,126 +5,126 @@
 #' difference, set difference).
 #' WARNING: All operations are in-place so please use \code{$copy}
 #' if you would like to perform an operation without destroying your current bitset.
-#' @importFrom R6 R6Class
+#'
+#' This class is defined as a named list for performance reasons, but for most
+#' intents and purposes it behaves just like an R6 class.
+#'
 #' @export
-Bitset <- R6Class(
-  'Bitset',
-  public = list(
-    #' @field .bitset a pointer to the underlying IterableBitset.
-    .bitset = NULL,
-
-    #' @field max_size the maximum size of the bitset.
-    max_size = 0,
-
-    #' @description create a bitset.
-    #' @param size the size of the bitset.
-    #' @param from pointer to an existing IterableBitset to use; if \code{NULL}
-    #' make empty bitset, otherwise copy existing bitset.
-    initialize = function(size, from = NULL) {
-      if (is.null(from)) {
-        self$.bitset <- create_bitset(size)
-      } else {
-        stopifnot(inherits(from, "externalptr"))
-        self$.bitset <- from
-      }
-      self$max_size <- bitset_max_size(self$.bitset)
-    },
-
-    #' @description insert into the bitset.
-    #' @param v an integer vector of elements to insert.
-    insert = function(v) {
-      bitset_insert(self$.bitset, v)
-      self
-    },
-
-    #' @description remove from the bitset.
-    #' @param v an integer vector of elements (not indices) to remove.
-    remove = function(v) {
-      bitset_remove(self$.bitset, v)
-      self
-    },
-
-    #' @description clear the bitset.
-    clear = function() {
-      bitset_clear(self$.bitset)
-      self
-    },
-
-    #' @description get the number of elements in the set.
-    size = function() bitset_size(self$.bitset),
-
-    #' @description to "bitwise or" or union two bitsets.
-    #' @param other the other bitset.
-    or = function(other) {
-      bitset_or(self$.bitset, other$.bitset)
-      self
-    },
-
-    #' @description to "bitwise and" or intersect two bitsets.
-    #' @param other the other bitset.
-    and = function(other) {
-      bitset_and(self$.bitset, other$.bitset)
-      self
-    },
-
-    #' @description to "bitwise not" or complement a bitset.
-    #' @param inplace whether to overwrite the current bitset, default = TRUE
-    not = function(inplace = TRUE) {
-      Bitset$new(from = bitset_not(self$.bitset, inplace))
-    },
-
-    #' @description to "bitwise xor" or get the symmetric difference of two bitset
-    #' (keep elements in either bitset but not in their intersection).
-    #' @param other the other bitset.
-    xor = function(other){
-      bitset_xor(self$.bitset, other$.bitset)
-      self
-    },
-
-    #' @description Take the set difference of this bitset with another
-    #' (keep elements of this bitset which are not in \code{other}).
-    #' @param other the other bitset.
-    set_difference = function(other){
-      bitset_set_difference(self$.bitset, other$.bitset)
-      self
-    },
-
-    #' @description sample a bitset.
-    #' @param rate the success probability for keeping each element, can be
-    #' a single value for all elements or a vector of unique
-    #' probabilities for keeping each element.
-    sample = function(rate) {
-      stopifnot(is.finite(rate), !is.null(rate))
-      if (length(rate) == 1) {
-        bitset_sample(self$.bitset, rate)
-      } else {
-        bitset_sample_vector(self$.bitset, rate)
-      }
-      self
-    },
-
-    #' @description choose k random items in the bitset
-    #' @param k the number of items in the bitset to keep. The selection of
-    #' these k items from N total items in the bitset is random, and
-    #' k should be chosen such that \eqn{0 \le k \le N}.
-    choose = function(k) {
-      stopifnot(is.finite(k))
-      stopifnot(k <= bitset_size(self$.bitset))
-      stopifnot(k >= 0)
-      if (k < self$max_size) {
-        bitset_choose(self$.bitset, as.integer(k))
-      }
-      self
-    },
-
-    #' @description returns a copy the bitset.
-    copy = function() Bitset$new(from = bitset_copy(self$.bitset)),
-
-    #' @description return an integer vector of the elements
-    #' stored in this bitset.
-    to_vector = function() bitset_to_vector(self$.bitset)
-
-  )
+Bitset <- list(
+  #' @description create a bitset.
+  #' @param size the size of the bitset.
+  #' @param from pointer to an existing IterableBitset to use; if \code{NULL}
+  #' make empty bitset, otherwise copy existing bitset.
+  new = function(size, from = NULL) {
+    if (is.null(from)) {
+      bitset <- create_bitset(size)
+    } else {
+      stopifnot(inherits(from, "externalptr"))
+      bitset <- from
+    }
+    max_size <- bitset_max_size(bitset)
+
+    self <- list(
+      .bitset = bitset,
+      max_size = max_size,
+
+      #' @description insert into the bitset.
+      #' @param v an integer vector of elements to insert.
+      insert = function(v) {
+        bitset_insert(self$.bitset, v)
+        self
+      },
+
+      #' @description remove from the bitset.
+      #' @param v an integer vector of elements (not indices) to remove.
+      remove = function(v) {
+        bitset_remove(self$.bitset, v)
+        self
+      },
+
+      #' @description clear the bitset.
+      clear = function() {
+        bitset_clear(self$.bitset)
+        self
+      },
+
+      #' @description get the number of elements in the set.
+      size = function() bitset_size(self$.bitset),
+
+      #' @description to "bitwise or" or union two bitsets.
+      #' @param other the other bitset.
+      or = function(other) {
+        bitset_or(self$.bitset, other$.bitset)
+        self
+      },
+
+      #' @description to "bitwise and" or intersect two bitsets.
+      #' @param other the other bitset.
+      and = function(other) {
+        bitset_and(self$.bitset, other$.bitset)
+        self
+      },
+
+      #' @description to "bitwise not" or complement a bitset.
+      #' @param inplace whether to overwrite the current bitset, default = TRUE
+      not = function(inplace = TRUE) {
+        Bitset$new(from = bitset_not(self$.bitset, inplace))
+      },
+
+      #' @description to "bitwise xor" or get the symmetric difference of two bitset
+      #' (keep elements in either bitset but not in their intersection).
+      #' @param other the other bitset.
+      xor = function(other){
+        bitset_xor(self$.bitset, other$.bitset)
+        self
+      },
+
+      #' @description Take the set difference of this bitset with another
+      #' (keep elements of this bitset which are not in \code{other}).
+      #' @param other the other bitset.
+      set_difference = function(other){
+        bitset_set_difference(self$.bitset, other$.bitset)
+        self
+      },
+
+      #' @description sample a bitset.
+      #' @param rate the success probability for keeping each element, can be
+      #' a single value for all elements or a vector of unique
+      #' probabilities for keeping each element.
+      sample = function(rate) {
+        stopifnot(is.finite(rate), !is.null(rate))
+        if (length(rate) == 1) {
+          bitset_sample(self$.bitset, rate)
+        } else {
+          bitset_sample_vector(self$.bitset, rate)
+        }
+        self
+      },
+
+      #' @description choose k random items in the bitset
+      #' @param k the number of items in the bitset to keep. The selection of
+      #' these k items from N total items in the bitset is random, and
+      #' k should be chosen such that \eqn{0 \le k \le N}.
+      choose = function(k) {
+        stopifnot(is.finite(k))
+        stopifnot(k <= bitset_size(self$.bitset))
+        stopifnot(k >= 0)
+        if (k < self$max_size) {
+          bitset_choose(self$.bitset, as.integer(k))
+        }
+        self
+      },
+
+      #' @description returns a copy the bitset.
+      copy = function() Bitset$new(from = bitset_copy(self$.bitset)),
+
+      #' @description return an integer vector of the elements
+      #' stored in this bitset.
+      to_vector = function() bitset_to_vector(self$.bitset)
+    )
+    class(self) <- 'Bitset'
+    self
+  }
 )
 
 #' @title Filter a bitset
diff --git a/tests/performance/bench-bitset.R b/tests/performance/bench-bitset.R
index 87899a1..1f2abff 100644
--- a/tests/performance/bench-bitset.R
+++ b/tests/performance/bench-bitset.R
@@ -88,6 +88,20 @@ ggplot(data = core_ops_bset) +
 
 limit_args_grid <- data.frame(limit = 10^(3:8))
 
+create_bset <- bench::press(
+  {
+    bench::mark(
+      min_iterations = 100,
+      check = FALSE,
+      filter_gc = TRUE,
+      {Bitset$new(size = limit)}
+    )
+  },
+  .grid = limit_args_grid
+)
+
+create_bset <- simplify_bench_output(create_bset)
+
 # clear
 clear_bset <- bench::press(
   {
@@ -119,6 +133,12 @@ not_bset <- bench::press(
 
 not_bset <- simplify_bench_output(out = not_bset)
 
+ggplot(data = create_bset) +
+  geom_violin(aes(x = expression, y = time, color = expression, fill = expression)) +
+  facet_wrap(. ~ limit, scales = "free") +
+  coord_flip() +
+  ggtitle("Create benchmark")
+
 ggplot(data = clear_bset) +
   geom_violin(aes(x = expression, y = time, color = expression, fill = expression)) +
   facet_wrap(. ~ limit, scales = "free") +
@@ -257,4 +277,4 @@ filter_bset <- simplify_bench_output(filter_bset)
 ggplot(data = filter_bset) +
   geom_violin(aes(x = as.factor(expression), y = time, color = expression, fill = expression)) +
   facet_wrap(size ~ limit, scales = "free") +
-  ggtitle("Sampling operations benchmark: filter")
\ No newline at end of file
+  ggtitle("Sampling operations benchmark: filter")