Add announcement for nanoarrow 0.2.0 release (#364)

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_posts/2023-06-13-nanoarrow-0.120-release.md

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+---
+layout: post
+title: "Apache Arrow nanoarrow 0.2 Release"
+date: "2023-06-22 00:00:00"
+author: pmc
+categories: [release]
+---
+<!--
+{% comment %}
+Licensed to the Apache Software Foundation (ASF) under one or more
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+(the "License"); you may not use this file except in compliance with
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+http://www.apache.org/licenses/LICENSE-2.0
+
+Unless required by applicable law or agreed to in writing, software
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+WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+See the License for the specific language governing permissions and
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+{% endcomment %}
+-->
+
+The Apache Arrow team is pleased to announce the 0.2.0 release of
+Apache Arrow nanoarrow. This initial release covers 19 resolved issues from
+6 contributors.
+
+## Release Highlights
+
+- Addition of the Arrow [IPC stream reader extension](#ipc-stream-support)
+- Addition of the [Getting Started with nanoarrow](#getting-started-with-nanoarrow)
+  tutorial
+- Improvements in reliability and platform test coverage of the [C library](#c-library)
+- Improvements in reliability and type support in the [R bindings](#r-bindings)
+
+See the
+[Changelog](https://github.com/apache/arrow-nanoarrow/blob/apache-arrow-nanoarrow-0.2.0/CHANGELOG.md)
+for a detailed list of contributions to this release.
+
+## IPC stream support
+
+This release includes support for reading schemas and record batches serialized
+using the
+[Arrow IPC format](https://arrow.apache.org/docs/format/Columnar.html#serialization-and-interprocess-communication-ipc). Based on the
+[flatcc](https://github.com/dvidelabs/flatcc)
+flatbuffers implementation, the nanoarrow IPC read support is implemented as
+an optional extension to the core nanoarrow library. The easiest way to get
+started is with the `ArrowArrayStream` provider using one of the built-in
+`ArrowIpcInputStream` implementations:
+
+```c
+#include <stdio.h>
+#include <stdbool.h>
+
+#include "nanoarrow_ipc.h"
+
+int main(int argc, char* argv[]) {
+  FILE* file_ptr = freopen(NULL, "rb", stdin);
+
+  struct ArrowIpcInputStream input;
+  NANOARROW_RETURN_NOT_OK(ArrowIpcInputStreamInitFile(&input, file_ptr, false));
+
+  struct ArrowArrayStream stream;
+  NANOARROW_RETURN_NOT_OK(ArrowIpcArrayStreamReaderInit(&stream, &input, NULL));
+
+  struct ArrowSchema schema;
+  NANOARROW_RETURN_NOT_OK(stream.get_schema(&stream, &schema));
+
+  struct ArrowArray array;
+  while (true) {
+    NANOARROW_RETURN_NOT_OK(stream.get_next(&stream, &array));
+    if (array.release == NULL) {
+      break;
+    }
+  }
+
+  return 0;
+}
+```
+
+Facilities for advanced usage are also provided via the low-level `ArrowIpcDecoder`,
+which takes care of the details of deserializing the flatbuffer headers and
+assembling buffers into an `ArrowArray`. The current implementation can read
+schema and record batch messages that contain any Arrow type that supported by
+the C data interface. The initial version can read both big and little endian
+streams originating from platforms of either endian. Dictionary encoding and
+compression are not currently supported.
+
+## Getting started with nanoarrow
+
+Early users of the nanoarrow C library respectfully noted that it was difficult
+to know where to begin. This release includes improvements in reference documentation
+but also includes a long-form tutorial for those just getting started with or
+considering adopting the library. You can find the tutorial at the
+[nanoarrow documentation site](https://apache.github.io/arrow-nanoarrow/dev/getting-started.html).
+
+## C library
+
+The nanoarrow 0.2.0 release also includes a number of bugfixes and improvements
+to the core C library, many of which were identified as a result of usage
+connected with development of the IPC extension.
+
+- Helpers for extracting/appending `Decimal128` and `Decimal256` elements
+  from/to arrays were added.
+- The C library can now perform "full" validation to validate untrusted input
+  (e.g., serialized IPC from the wire).
+- The C library can now perform "minimal" validation that performs all checks
+  that do not access any buffer data. This feature was added to facilitate
+  future support for the `ArrowDeviceArray` that was recently added as the
+  Arrow C device interface.
+- Release verification on Ubuntu (x86_64, arm64), Fedora (x86_64),
+  Archlinux (x86_64), Centos 7 (x86_64, arm64), Alpine (x86_64, arm64, s390x),
+  Windows (x86_64), and MacOS (x86_64) were added to the continuous
+  integration system. Linux verification is implemented using `docker compose`
+  to facilitate local checks when developing features that may affect
+  a specific platform.
+
+## R bindings
+
+The nanoarrow R bindings are distributed as the `nanoarrow` package on
+[CRAN](https://cran.r-project.org/). The 0.2.0 release of the R bindings includes
+improvements in type support, improvements in stability, and features required
+for the forthcoming release of Arrow Database Connectivity (ADBC) R bindings.
+Notably:
+
+- Support for conversion of union arrays to R objects was added to facilitate
+  support for an ADBC function that returns such an array.
+- Support for adding an R-level finalizer to an `ArrowArrayStream` was added
+  to facilitate safely wrapping a stream resulting from an ADBC call at the
+  R level.
+
+## Python bindings?
+
+The nanoarrow 0.2.0 release does not include Python bindings, but improvements to the
+[unreleased draft bindings](https://github.com/apache/arrow-nanoarrow/tree/main/python)
+were added to facilitate discussion among Python developers regarding the useful
+scope of a potential future nanoarrow Python package. If one of those developers is
+you, feel free to
+[open an issue](https://github.com/apache/arrow-nanoarrow/issues/new/choose)
+or send a post to the
+[developer mailing list](https://lists.apache.org/[email protected])
+to engage in the discussion.
+
+## Contributors
+
+This initial release consists of contributions from 6 contributors in addition
+to the invaluable advice and support of the Apache Arrow developer mailing list.
+Special thanks to David Li for reviewing nearly every PR in this release!
+
+```
+$ git shortlog -sn d91c35b33c7b6ff94f5f929384879352e241ed71..apache-arrow-nanoarrow-0.2.0 | grep -v "GitHub Actions"
+    61  Dewey Dunnington
+     2  Dirk Eddelbuettel
+     2  Joris Van den Bossche
+     2  Kirill Müller
+     2  William Ayd
+     1  David Li
+```