Build a client over the stdio transport, exchanging newline-delimited
JSON-RPC over the supplied readLine/writeLine channel (symmetric to
mcp.transport.stdio.serveStdio). readLine returns the next server line
(without its terminator) or null at end-of-input; writeLine emits one
message line (the sink appends the terminator).
Build a client over the stdio transport, exchanging newline-delimited JSON-RPC over the supplied readLine/writeLine channel (symmetric to mcp.transport.stdio.serveStdio). readLine returns the next server line (without its terminator) or null at end-of-input; writeLine emits one message line (the sink appends the terminator).