[Doc] Add reader docs

Author: haochengxia

docs/mkdocs.yml

@@ -12,7 +12,8 @@ nav:
     - Getting Started: 
       - getting_started/quickstart.md
       - getting_started/installation.md
-    - Examples: 
+    - Examples:
+      - examples/reader.md
       - examples/simulation.md
       - examples/analysis.md
       - examples/plugins.md

docs/src/en/examples/reader.md

@@ -0,0 +1,55 @@
+# Trace Reader
+
+We support a unified trace reader to open trace files in different format and read the requests.
+
+## Basic usage
+
+`TraceReader` class is the core of this functionality. When we create an instance of `TraceReader`, we open a trace file for read requests.
+
+`TraceReader` accepts three arguments:
+- `trace: str | TraceReader`: A trace path or other trace instance. The trace path can be a file path on your local machine (e.g., ~/data/trace.oracleGeneral.zst) or an S3 URI (e.g., s3://cache-datasets/cache_dataset_oracleGeneral/2007_msr/msr_hm_0.oracleGeneral.zst).
+- `trace_type: TraceType` (optional): If not given, it will be infered according to the file name.
+- `reader_init_params: ReaderInitParam` (optional): If not given, will use default params for reader initialization.
+
+Here is an example to load one trace via an S3 URI.
+
+```python
+import libcachesim as lcs
+
+# Open a trace hosted on S3 (find more via https://github.com/cacheMon/cache_dataset)
+URI = "s3://cache-datasets/cache_dataset_oracleGeneral/2007_msr/msr_hm_0.oracleGeneral.zst"
+reader = lcs.TraceReader(
+    trace = URI,
+    trace_type = lcs.TraceType.ORACLE_GENERAL_TRACE,
+    reader_init_params = lcs.ReaderInitParam(ignore_obj_size=False)
+)
+```
+
+Then we can walk through the trace.
+
+```python
+for req in reader:
+    print(req.obj_id, req.obj_size)
+```
+
+## Reader slicing
+
+`TraceReader` support slicing and index access.
+
+```python
+# Read the first 100 reqs
+for req in reader[:100]:
+    print(req.obj_id, req.obj_size)
+```
+
+```python
+# Read 100 reqs after the first 100 reqs 
+for req in reader[100:200]:
+    print(req.obj_id, req.obj_size)
+```
+
+```python
+# Read last 100 reqs
+for req in reader[-100:]:
+    print(req.obj_id, req.obj_size)
+```