Struct Builder 

pub struct Builder<'p> { /* private fields */ }

Owns one pooled buffer. Build a message with root(), then:

• finished(): borrow it until the next root() (no atomics);
• seal() … take_frames(): batch length-prefixed frames into one Bytes (one refcount per batch — the fast path for senders);
• flush(): one owned Bytes per message (one refcount per message);
• finish(): like flush(), and the buffer goes back to the pool.

Every message is written after a 4-byte slot that seal() fills with its length, so frames are [u32 len][message] with no extra copy.

A builder made with Builder::new_enveloped reserves a HEADER_LEN-byte slot instead, which flush_envelope() / seal_envelope() fill with an envelope header (the CRC is appended after the message) — again without copying the payload. finished() / flush() still return the bare message in either mode; seal() only works in the default mode and seal_envelope() / flush_envelope() only in the enveloped one (otherwise: panic “builder mode mismatch”).

Implementations

impl<'p> Builder<'p>

pub fn new(pool: &'p dyn BufPool) -> Self

pub fn new_enveloped(pool: &'p dyn BufPool) -> Self

A builder whose messages can be emitted as envelopes (crate::envelope) with flush_envelope() / seal_envelope() without copying: a HEADER_LEN-byte slot is reserved before each one.

pub fn root(&mut self, fixed_len: u16) -> TableW<'_>

Start the root table of a new message (an unsealed previous message is discarded).

pub fn root_fixed<const N: usize>(&mut self) -> FixedW<'_, N>

Root table with only scalar fields (no pointers) and compile-time size N.

pub fn finished(&self) -> Result<&[u8], Error>

Borrow the current message without freezing it (no refcount traffic). Valid until the next root() — the equivalent of FlatBuffers’ finished_data().

pub fn seal(&mut self) -> Result<(), Error>

Seal the current message as a frame [u32 len][message] in the pending batch. No atomics; a no-op when there is no current message.

pub fn sealed_len(&self) -> usize

Bytes of sealed frames pending in the batch (to ship by size).

pub fn take_frames(&mut self) -> Bytes

Freeze every sealed frame as one Bytes (one refcount for the whole batch) and start an empty batch. An unsealed message is discarded. Split the result back into messages with crate::frames.

pub fn flush(&mut self) -> Result<Bytes, Error>

Freeze the current message alone (without its length slot) and keep the builder. One refcount per message. Panics if sealed frames are pending (call take_frames first).

pub fn seal_envelope(&mut self, schema_id: u64) -> Result<(), Error>

Seal the current message as an envelope in the pending batch, so take_frames() returns concatenated envelopes (split them with envelope::envelopes). A no-op when there is no current message. Panics with “builder mode mismatch” unless built with new_enveloped.

pub fn flush_envelope(&mut self, schema_id: u64) -> Result<Bytes, Error>

Freeze the current message as one envelope (header + message + CRC) and keep the builder; the payload is not copied. Returns an empty Bytes when there is no current message. Panics with “builder mode mismatch” unless built with new_enveloped, and if sealed frames are pending (call take_frames first).

pub fn finish(self) -> Result<Bytes, Error>

Freeze the message; the buffer goes back to the pool.

Trait Implementations

impl Drop for Builder<'_>

fn drop(&mut self)

Executes the destructor for this type.