Holds JSON bytes that have already been encoded and are written verbatim.

A build encodes every artifact exactly once. The same canonical bytes are hashed for collection.json and spliced into the file's envelope, so neither the digest nor the write encodes the payload again. Wrapping those bytes in a struct lets DocShell.Artifact.write_raw/3 and DocShell.Artifact.Transaction.write/2 tell them apart from a JSON term that still needs encoding.

iodata is never flattened into a single binary: writers pass it straight to the file descriptor, which keeps a large artifact from being copied in memory before it reaches disk. Build one with DocShell.Artifact.encode/2 or DocShell.Artifact.encode_envelope/4 rather than by hand, so the bytes are guaranteed to be valid JSON.