class GuestConsole

Initialize the socket, attempting to reach a state where the socket appears

'stable' with respect to output.

This skips over initial startup noise (such as boot logs, etc) that may be

present on the socket interface. However, no guarantee can be made on the

state of the guest and whether it is actually finished starting up services

or even started listening for input on the serial line.

Aborts with the error ZX_ERR_TIMEOUT if `deadline` is reached

prior to the system reaching its shell.

Executes a command and waits for a response. Uses a header and a footer to

ensure the command finished executing and to capture output. Blocks on the

serial socket being writable and readable at various points and on the

command completing. If provided, the nonce helps disambiguate multiple

attempts of the same command.

Sends a message to the guest's serial. Blocks until the entire message is

written to the socket but doesn't wait for a response.

Waits for a marker string to be read from the guest's serial, or until an

internal timeout passes. Optionally fills |result| with everything read up

to (but excluding) |marker|.

Returns ZX_OK if the string was read before the timeout expired, and

an error status in other cases.

The class keeps an internal buffer of unread serial data. This function

will consume all of the buffer up to the first occurance of |marker|.

For example, if the underlying socket has the following data on it:

"xxxmarkeryyy"

then a call `WaitForMarker("marker",

&result

)` will return `xxx` in

|result|, and consume the buffer so that only `yyy` remains.

Waits for the socket interface to be closed, or a deadline is reached.

Repeatedly execute a command until the desired output is seen. This

essentially retries the command using ExecuteBlocking at the specified rate

until it either succeeds and the output is matched, or the overall deadline

expires and this returns with an error.

This is intended to be used when a guest is starting up and it is ambiguous

whether it is even listening for input yet.