[rust] Derive Eq + PartialEq on FieldLoc and FlatBufferBuilder (googl…

…e#5394)

rust/flatbuffers/src/builder.rs

@@ -31,7 +31,7 @@ use vector::{SafeSliceAccess, Vector};
 
 pub const N_SMALLVEC_STRING_VECTOR_CAPACITY: usize = 16;
 
-#[derive(Clone, Copy, Debug)]
+#[derive(Clone, Copy, Debug, Eq, PartialEq)]
 struct FieldLoc {
     off: UOffsetT,
     id: VOffsetT,
@@ -40,7 +40,7 @@ struct FieldLoc {
 /// FlatBufferBuilder builds a FlatBuffer through manipulating its internal
 /// state. It has an owned `Vec<u8>` that grows as needed (up to the hardcoded
 /// limit of 2GiB, which is set by the FlatBuffers format).
-#[derive(Clone, Debug)]
+#[derive(Clone, Debug, Eq, PartialEq)]
 pub struct FlatBufferBuilder<'fbb> {
     owned_buf: Vec<u8>,
     head: usize,