End the Spear.stream! stream early when reading a chunk smaller than …

…requested

lib/spear/reading/stream.ex

@@ -11,7 +11,9 @@ defmodule Spear.Reading.Stream do
     :resolve_links?,
     :timeout,
     :buffer,
-    :credentials
+    :credentials,
+    # The number of messages read from a single chunk.
+    read_count: 0
   ]
 
   @type t :: %__MODULE__{}
@@ -90,17 +92,24 @@ defmodule Spear.Reading.Stream do
     )
   end
 
-  # in this case the buffer has run dry and we need to request more events
-  # (a new buffer) with a new ReadReq
   @spec unfold_continuous(t()) :: {emitted_element :: tuple(), t()} | nil
+  defp unfold_continuous(%__MODULE__{buffer: <<>>, read_count: read_count, max_count: max_count})
+       when read_count < max_count do
+    # If we are done reading this chunk and the amount that we read is smaller than
+    # what we requested, the stream must be finished.
+    nil
+  end
+
   defp unfold_continuous(%__MODULE__{buffer: <<>>, from: from} = state) do
+    # in this case the buffer has run dry and we need to request more events
+    # (a new buffer) with a new ReadReq
     response = request!(%__MODULE__{state | max_count: state.max_count + 1})
 
     # discard the first message since it is `from`
     with {^from, <<_head, _::binary>> = rest} <- unfold_chunk(response),
          # look ahead in `rest` to ensure it's an event read response
          {event(), _} <- unfold_chunk(rest) do
-      unfold_continuous(%__MODULE__{state | buffer: rest})
+      unfold_continuous(%__MODULE__{state | buffer: rest, read_count: 0})
     else
       # discard trailing stream position message
       _ ->
@@ -111,7 +120,13 @@ defmodule Spear.Reading.Stream do
   defp unfold_continuous(%__MODULE__{buffer: buffer} = state) do
     case unfold_chunk(buffer) do
       {event() = message, remaining_buffer} ->
-        {message, %__MODULE__{state | buffer: remaining_buffer, from: message}}
+        {message,
+         %__MODULE__{
+           state
+           | buffer: remaining_buffer,
+             from: message,
+             read_count: state.read_count + 1
+         }}
 
       # skip non-event read responses
       # coveralls-ignore-start