GH-39870: [Go] Include buffered pages in TotalBytesWritten (#40105)

### Rationale for this change

Currently, buffered data pages are not included in TotalBytesWritten this means that their is not an accurate estimate of the size of the current size. 

### Are there any user-facing changes?
`RowGroupTotalBytesWritten` will include the TotalBytes in buffered DataPages minus the buffered data pages headers. 

* Closes: #39870

Authored-by: Matthew McNew <[email protected]>
Signed-off-by: Matt Topol <[email protected]>

go/parquet/file/column_writer.go

@@ -198,7 +198,12 @@ func (w *columnWriter) TotalCompressedBytes() int64 {
 }
 
 func (w *columnWriter) TotalBytesWritten() int64 {
-	return w.totalBytesWritten
+	bufferedPagesBytes := int64(0)
+	for _, p := range w.pages {
+		bufferedPagesBytes += int64(len(p.Data()))
+	}
+
+	return w.totalBytesWritten + bufferedPagesBytes
 }
 
 func (w *columnWriter) RowsWritten() int {

go/parquet/file/column_writer_test.go

@@ -430,6 +430,11 @@ func (p *PrimitiveWriterTestSuite) testDictionaryFallbackEncoding(version parque
 }
 
 func (p *PrimitiveWriterTestSuite) testDictionaryFallbackAndCompressedSize(version parquet.Version) {
+	// skip boolean as dictionary encoding is not used
+	if p.Typ.Kind() == reflect.Bool {
+		return
+	}
+
 	p.GenerateData(SmallSize)
 	props := parquet.DefaultColumnProperties()
 	props.DictionaryEnabled = true
@@ -440,13 +445,14 @@ func (p *PrimitiveWriterTestSuite) testDictionaryFallbackAndCompressedSize(versi
 		props.Encoding = parquet.Encodings.RLEDict
 	}
 
-	writer := p.buildWriter(SmallSize, props, parquet.WithVersion(version))
+	writer := p.buildWriter(SmallSize, props, parquet.WithVersion(version), parquet.WithDataPageSize(SmallSize-1))
 	p.WriteBatchValues(writer, nil, nil)
+	p.NotZero(writer.TotalBytesWritten())
 	writer.FallbackToPlain()
-	p.NotEqual(0, writer.TotalCompressedBytes())
+	p.NotZero(writer.TotalCompressedBytes())
 	writer.Close()
-	p.NotEqual(0, writer.TotalCompressedBytes())
-	p.NotEqual(0, writer.TotalBytesWritten())
+	p.NotZero(writer.TotalCompressedBytes())
+	p.NotZero(writer.TotalBytesWritten())
 }
 
 func (p *PrimitiveWriterTestSuite) TestRequiredPlain() {