Move array data into IPC (#1892)

It's IPC-specific now

Author: gatesn

vortex-flatbuffers/flatbuffers/vortex-array/array.fbs

@@ -1,16 +1,5 @@
 include "vortex-scalar/scalar.fbs";
 
-/// An ArrayData describes the hierarchy of an array as well as the locations of the data buffers that appear
-/// immediately after the message in the byte stream.
-table ArrayData {
-    /// The array's hierarchical definition.
-    array: Array;
-    /// The row count of the array.
-    row_count: uint64;
-    /// The locations of the data buffers of the array, in ascending order of offset.
-    buffers: [Buffer];
-}
-
 table Array {
     encoding: uint16;
     metadata: [ubyte];
@@ -33,14 +22,4 @@ table ArrayStats {
     uncompressed_size_in_bytes: uint64 = null;
 }
 
-table Buffer {
-    /// The length of the buffer in bytes.
-    length: uint64;
-    /// The length of any padding bytes written immediately following the buffer.
-    padding: uint16;
-    /// The minimum alignment of the buffer.
-    alignment: uint16;
-}
-
 root_type Array;
-root_type ArrayData;

vortex-flatbuffers/flatbuffers/vortex-serde/message.fbs

@@ -9,8 +9,28 @@ enum Compression: uint8 {
     None = 0,
 }
 
+/// An ArrayData describes the hierarchy of an array as well as the locations of the data buffers that appear
+/// immediately after the message in the byte stream.
+table ArrayMessage {
+    /// The array's hierarchical definition.
+    array: Array;
+    /// The row count of the array.
+    row_count: uint64;
+    /// The locations of the data buffers of the array, in ascending order of offset.
+    buffers: [Buffer];
+}
+
+table Buffer {
+    /// The length of the buffer in bytes.
+    length: uint64;
+    /// The length of any padding bytes written immediately following the buffer.
+    padding: uint16;
+    /// The minimum alignment of the buffer.
+    alignment: uint16;
+}
+
 union MessageHeader {
-    ArrayData,
+    ArrayMessage,
     Buffer,
     DType,
 }