Imports of sse command

PathSynopsis
contextPackage context defines the Context type, which carries deadlines, cancellation signals, and other request-scoped values across API boundaries and between processes.
flagPackage flag implements command-line flag parsing.
golang.org/x/tools/internal/mcpTODO: consider passing Transport to NewClient and merging {Connection,Client}Options
logPackage log implements a simple logging package.
net/httpPackage http provides HTTP client and server implementations.