Struct RpcClient 

pub struct RpcClient<S> { /* private fields */ }

A minimal Cap’n Proto RPC client for tunnel registration.

Implements the exact wire sequence cloudflared uses on its control stream: bootstrap to obtain the peer’s main interface, then call/return/finish for each registration method. Question ids are allocated monotonically from 0 and the bootstrapped capability is tracked as import id 0.

All capnp message construction and decoding happens in synchronous helpers so no non-Send capnp state is held across an await, keeping every future Send.

Implementations

impl<S: AsyncStream + Unpin> RpcClient<S>

pub fn new(stream: S) -> Self

Wraps a bidirectional stream as an RPC client.

pub fn into_inner(self) -> S

Returns the underlying stream (the connection stays open).

pub async fn bootstrap(&mut self) -> Result<u32, RpcError>

Sends Message::bootstrap and waits for the return carrying the peer’s main interface. Returns the import id to use for calls.

pub async fn call<T>( &mut self, import_identifier: u32, interface_identifier: u64, method_identifier: u16, fill_parameters: impl FnOnce(&mut Builder<'_>) -> Result<(), RpcError>, decode: impl FnOnce(Reader<'_>) -> Result<T, RpcError>, ) -> Result<T, RpcError>

Performs a method call on an imported capability, decodes the results payload with decode, then sends finish for the question.

pub async fn close(self) -> Result<S, RpcError>

Releases the bootstrapped capability and returns the underlying stream. Sends Message::release for import id 0, mirroring what capnp-go sends when a registration client is closed.