diff --git a/src/requests/models.py b/src/requests/models.py
index 8f56ca7d23..d90da6d4ae 100644
--- a/src/requests/models.py
+++ b/src/requests/models.py
@@ -65,6 +65,9 @@
     super_len,
     to_key_val_list,
 )
+from requests.exceptions import ChunkedEncodingError, ConnectionError, ContentDecodingError, SSLError as RequestsSSLError, StreamConsumedError
+from requests.cookies import cookiejar_from_dict
+from requests.structures import CaseInsensitiveDict
 
 #: The set of HTTP status codes that indicate an automatically
 #: processable redirect.
@@ -812,46 +815,36 @@ def iter_content(self, chunk_size=1, decode_unicode=False):
         If decode_unicode is True, content will be decoded using the best
         available encoding based on the response.
         """
-
-        def generate():
-            # Special case for urllib3.
-            if hasattr(self.raw, "stream"):
+        if self._content_consumed and isinstance(self._content, bool):
+            raise StreamConsumedError()
+        if chunk_size is not None and not isinstance(chunk_size, int):
+            raise TypeError(
+                f"chunk_size must be an int, it is instead a {type(chunk_size)}."
+            )
+        
+        def generate(raw, chunk_size):
+            if hasattr(raw, "stream"):
                 try:
-                    yield from self.raw.stream(chunk_size, decode_content=True)
-                except ProtocolError as e:
-                    raise ChunkedEncodingError(e)
-                except DecodeError as e:
-                    raise ContentDecodingError(e)
-                except ReadTimeoutError as e:
-                    raise ConnectionError(e)
-                except SSLError as e:
-                    raise RequestsSSLError(e)
+                    yield from raw.stream(chunk_size, decode_content=True)
+                except (ProtocolError, DecodeError, ReadTimeoutError, SSLError) as e:
+                    if isinstance(e, ProtocolError):
+                        raise ChunkedEncodingError(e)
+                    elif isinstance(e, DecodeError):
+                        raise ContentDecodingError(e)
+                    elif isinstance(e, ReadTimeoutError):
+                        raise ConnectionError(e)
+                    elif isinstance(e, SSLError):
+                        raise RequestsSSLError(e)
             else:
-                # Standard file-like object.
                 while True:
-                    chunk = self.raw.read(chunk_size)
+                    chunk = raw.read(chunk_size)
                     if not chunk:
                         break
                     yield chunk
-
             self._content_consumed = True
-
-        if self._content_consumed and isinstance(self._content, bool):
-            raise StreamConsumedError()
-        elif chunk_size is not None and not isinstance(chunk_size, int):
-            raise TypeError(
-                f"chunk_size must be an int, it is instead a {type(chunk_size)}."
-            )
-        # simulate reading small chunks of the content
-        reused_chunks = iter_slices(self._content, chunk_size)
-
-        stream_chunks = generate()
-
-        chunks = reused_chunks if self._content_consumed else stream_chunks
-
-        if decode_unicode:
-            chunks = stream_decode_response_unicode(chunks, self)
-
+        
+        reused_chunks = iter_slices(self._content, chunk_size) if self._content_consumed else generate(self.raw, chunk_size)
+        chunks = stream_decode_response_unicode(reused_chunks, self) if decode_unicode else reused_chunks
         return chunks
 
     def iter_lines(
@@ -1035,3 +1028,7 @@ def close(self):
         release_conn = getattr(self.raw, "release_conn", None)
         if release_conn is not None:
             release_conn()
+    
+    def close(self):
+        if self.raw and hasattr(self.raw, "close"):
+            self.raw.close()
diff --git a/src/requests/utils.py b/src/requests/utils.py
index 699683e5d9..8409166cef 100644
--- a/src/requests/utils.py
+++ b/src/requests/utils.py
@@ -58,6 +58,8 @@
     UnrewindableBodyError,
 )
 from .structures import CaseInsensitiveDict
+from requests.cookies import cookiejar_from_dict
+from requests.structures import CaseInsensitiveDict
 
 NETRC_FILES = (".netrc", "_netrc")
 
@@ -566,12 +568,12 @@ def get_encoding_from_headers(headers):
 
 def stream_decode_response_unicode(iterator, r):
     """Stream decodes an iterator."""
-
-    if r.encoding is None:
+    encoding = r.encoding
+    if encoding is None:
         yield from iterator
         return
 
-    decoder = codecs.getincrementaldecoder(r.encoding)(errors="replace")
+    decoder = codecs.getincrementaldecoder(encoding)(errors="replace")
     for chunk in iterator:
         rv = decoder.decode(chunk)
         if rv:
@@ -583,12 +585,9 @@ def stream_decode_response_unicode(iterator, r):
 
 def iter_slices(string, slice_length):
     """Iterate over slices of a string."""
-    pos = 0
     if slice_length is None or slice_length <= 0:
         slice_length = len(string)
-    while pos < len(string):
-        yield string[pos : pos + slice_length]
-        pos += slice_length
+    return (string[pos:pos + slice_length] for pos in range(0, len(string), slice_length))
 
 
 def get_unicode_from_response(r):