def dump(obj, fp, skipkeys=False, ensure_ascii=True, check_circular=True,
         allow_nan=True, cls=None, indent=None, separators=None,
         encoding='utf-8', default=None, use_decimal=True,
         namedtuple_as_object=True, tuple_as_array=True,
         bigint_as_string=False, sort_keys=False, item_sort_key=None,
         for_json=False, ignore_nan=False, int_as_string_bitcount=None,
         iterable_as_array=False, **kw):
    """Serialize ``obj`` as a JSON formatted stream to ``fp`` (a
    ``.write()``-supporting file-like object).

    If *skipkeys* is true then ``dict`` keys that are not basic types
    (``str``, ``unicode``, ``int``, ``long``, ``float``, ``bool``, ``None``)
    will be skipped instead of raising a ``TypeError``.

    If *ensure_ascii* is false, then the some chunks written to ``fp``
    may be ``unicode`` instances, subject to normal Python ``str`` to
    ``unicode`` coercion rules. Unless ``fp.write()`` explicitly
    understands ``unicode`` (as in ``codecs.getwriter()``) this is likely
    to cause an error.

    If *check_circular* is false, then the circular reference check
    for container types will be skipped and a circular reference will
    result in an ``OverflowError`` (or worse).

    If *allow_nan* is false, then it will be a ``ValueError`` to
    serialize out of range ``float`` values (``nan``, ``inf``, ``-inf``)
    in strict compliance of the original JSON specification, instead of using
    the JavaScript equivalents (``NaN``, ``Infinity``, ``-Infinity``). See
    *ignore_nan* for ECMA-262 compliant behavior.

    If *indent* is a string, then JSON array elements and object members
    will be pretty-printed with a newline followed by that string repeated
    for each level of nesting. ``None`` (the default) selects the most compact
    representation without any newlines. For backwards compatibility with
    versions of simplejson earlier than 2.1.0, an integer is also accepted
    and is converted to a string with that many spaces.

    If specified, *separators* should be an
    ``(item_separator, key_separator)`` tuple.  The default is ``(', ', ': ')``
    if *indent* is ``None`` and ``(',', ': ')`` otherwise.  To get the most
    compact JSON representation, you should specify ``(',', ':')`` to eliminate
    whitespace.

    *encoding* is the character encoding for str instances, default is UTF-8.

    *default(obj)* is a function that should return a serializable version
    of obj or raise ``TypeError``. The default simply raises ``TypeError``.

    If *use_decimal* is true (default: ``True``) then decimal.Decimal
    will be natively serialized to JSON with full precision.

    If *namedtuple_as_object* is true (default: ``True``),
    :class:`tuple` subclasses with ``_asdict()`` methods will be encoded
    as JSON objects.

    If *tuple_as_array* is true (default: ``True``),
    :class:`tuple` (and subclasses) will be encoded as JSON arrays.

    If *iterable_as_array* is true (default: ``False``),
    any object not in the above table that implements ``__iter__()``
    will be encoded as a JSON array.

    If *bigint_as_string* is true (default: ``False``), ints 2**53 and higher
    or lower than -2**53 will be encoded as strings. This is to avoid the
    rounding that happens in Javascript otherwise. Note that this is still a
    lossy operation that will not round-trip correctly and should be used
    sparingly.

    If *int_as_string_bitcount* is a positive number (n), then int of size
    greater than or equal to 2**n or lower than or equal to -2**n will be
    encoded as strings.

    If specified, *item_sort_key* is a callable used to sort the items in
    each dictionary. This is useful if you want to sort items other than
    in alphabetical order by key. This option takes precedence over
    *sort_keys*.

    If *sort_keys* is true (default: ``False``), the output of dictionaries
    will be sorted by item.

    If *for_json* is true (default: ``False``), objects with a ``for_json()``
    method will use the return value of that method for encoding as JSON
    instead of the object.

    If *ignore_nan* is true (default: ``False``), then out of range
    :class:`float` values (``nan``, ``inf``, ``-inf``) will be serialized as
    ``null`` in compliance with the ECMA-262 specification. If true, this will
    override *allow_nan*.

    To use a custom ``JSONEncoder`` subclass (e.g. one that overrides the
    ``.default()`` method to serialize additional types), specify it with
    the ``cls`` kwarg. NOTE: You should use *default* or *for_json* instead
    of subclassing whenever possible.

    """
    # cached encoder
    if (not skipkeys and ensure_ascii and
        check_circular and allow_nan and
        cls is None and indent is None and separators is None and
        encoding == 'utf-8' and default is None and use_decimal
        and namedtuple_as_object and tuple_as_array and not iterable_as_array
        and not bigint_as_string and not sort_keys
        and not item_sort_key and not for_json
        and not ignore_nan and int_as_string_bitcount is None
        and not kw
    ):
        iterable = _default_encoder.iterencode(obj)
    else:
        if cls is None:
            cls = JSONEncoder
        iterable = cls(skipkeys=skipkeys, ensure_ascii=ensure_ascii,
            check_circular=check_circular, allow_nan=allow_nan, indent=indent,
            separators=separators, encoding=encoding,
            default=default, use_decimal=use_decimal,
            namedtuple_as_object=namedtuple_as_object,
            tuple_as_array=tuple_as_array,
            iterable_as_array=iterable_as_array,
            bigint_as_string=bigint_as_string,
            sort_keys=sort_keys,
            item_sort_key=item_sort_key,
            for_json=for_json,
            ignore_nan=ignore_nan,
            int_as_string_bitcount=int_as_string_bitcount,
            **kw).iterencode(obj)
    # could accelerate with writelines in some versions of Python, at
    # a debuggability cost
    for chunk in iterable:
        fp.write(chunk)