fix is_fast for bytes field

src/aggregation/bucket/term_agg.rs

@@ -104,6 +104,10 @@ pub struct TermsAggregation {
     /// Set the order. `String` is here a target, which is either "_count", "_key", or the name of
     /// a metric sub_aggregation.
     ///
+    /// Single value metrics like average can be adressed by its name.
+    /// Multi value metrics like stats are required to adress their field by name e.g.
+    /// "stats.avg"
+    ///
     /// Examples in JSON format:
     /// { "_count": "asc" }
     /// { "_key": "asc" }

src/schema/field_type.rs

@@ -188,13 +188,14 @@ impl FieldType {
     /// returns true if the field is fast.
     pub fn is_fast(&self) -> bool {
         match *self {
+            FieldType::Bytes(ref bytes_options) => bytes_options.is_fast(),
             FieldType::Str(ref text_options) => text_options.is_fast(),
             FieldType::U64(ref int_options)
             | FieldType::I64(ref int_options)
             | FieldType::F64(ref int_options)
             | FieldType::Date(ref int_options) => int_options.get_fastfield_cardinality().is_some(),
             FieldType::Facet(_) => true,
-            _ => false,
+            FieldType::JsonObject(_) => false,
         }
     }