apacheGH-40493: [GLib][Ruby] Add GArrowStreamDecoder

This is the bindings of
`arrow::ipc::StreamDecoder`. `arrow::ipc::StreamDecoder` is useful to
integrate async input.

c_glib/Gemfile

@@ -20,4 +20,4 @@
 source "https://rubygems.org/"
 
 gem "test-unit"
-gem "gobject-introspection", ">= 4.1.1"
+gem "gobject-introspection", ">= 4.2.3"

c_glib/arrow-glib/internal-hash-table.hpp

@@ -37,3 +37,21 @@ garrow_internal_hash_table_to_metadata(GHashTable *metadata)
     &arrow_metadata);
   return arrow_metadata;
 }
+
+static inline GHashTable *
+garrow_internal_hash_table_from_metadata(
+  const std::shared_ptr<arrow::KeyValueMetadata> &arrow_metadata)
+{
+  auto metadata = g_hash_table_new_full(g_str_hash, g_str_equal, g_free, g_free);
+  const auto &keys = arrow_metadata->keys();
+  const auto &values = arrow_metadata->values();
+  auto n = arrow_metadata->size();
+  for (int64_t i = 0; i < n; ++i) {
+    const auto &key = keys[i];
+    const auto &value = values[i];
+    g_hash_table_insert(metadata,
+                        g_strndup(key.data(), key.size()),
+                        g_strndup(value.data(), value.size()));
+  }
+  return metadata;
+}